utils: ipc: import mojo

Import mojo from the Chromium repository, so that we can use it for
generating code for the IPC mechanism. The commit from which this was
taken is:
a079161ec8c6907b883f9cb84fc8c4e7896cb1d0 "Add PPAPI constructs for
sending focus object to PdfAccessibilityTree"

This tree has been pruned to remove directories that didn't have any
necessary code:
- mojo/* except for mojo/public
  - mojo core, docs, and misc files
- mojo/public/* except for mojo/public/{tools,LICENSE}
  - language bindings for IPC, tests, and some mojo internals
- mojo/public/tools/{fuzzers,chrome_ipc}
- mojo/public/tools/bindings/generators
  - code generation for other languages

No files were modified.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

14 files changed, 3973 insertions, 0 deletions

diff --git a/utils/ipc/mojo/public/tools/bindings/BUILD.gn b/utils/ipc/mojo/public/tools/bindings/BUILD.gn
new file mode 100644
index 00000000..8ba6e922
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/BUILD.gn
@@ -0,0 +1,108 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//mojo/public/tools/bindings/mojom.gni")
+import("//third_party/jinja2/jinja2.gni")
+
+action("precompile_templates") {
+  sources = mojom_generator_sources
+  sources += [
+    "$mojom_generator_root/generators/cpp_templates/enum_macros.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/enum_serialization_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_macros.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_proxy_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_request_validator_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_response_validator_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/interface_stub_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-forward.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-import-headers.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-params-data.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-shared-internal.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-shared-message-ids.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-shared.cc.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-shared.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-test-utils.cc.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module-test-utils.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module.cc.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/module.h.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_data_view_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_data_view_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_macros.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_serialization_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_traits_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_traits_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/struct_unserialized_message_context.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_data_view_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_data_view_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_serialization_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_traits_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/union_traits_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/validation_macros.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_class_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_class_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_class_template_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_union_class_declaration.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_union_class_definition.tmpl",
+    "$mojom_generator_root/generators/cpp_templates/wrapper_union_class_template_definition.tmpl",
+    "$mojom_generator_root/generators/java_templates/constant_definition.tmpl",
+    "$mojom_generator_root/generators/java_templates/constants.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/data_types_definition.tmpl",
+    "$mojom_generator_root/generators/java_templates/enum.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/enum_definition.tmpl",
+    "$mojom_generator_root/generators/java_templates/header.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/interface.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/interface_definition.tmpl",
+    "$mojom_generator_root/generators/java_templates/interface_internal.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/struct.java.tmpl",
+    "$mojom_generator_root/generators/java_templates/union.java.tmpl",
+    "$mojom_generator_root/generators/js_templates/enum_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/externs/interface_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/externs/module.externs.tmpl",
+    "$mojom_generator_root/generators/js_templates/externs/struct_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/fuzzing.tmpl",
+    "$mojom_generator_root/generators/js_templates/interface_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/enum_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/interface_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/module_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/mojom-lite.js.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/struct_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/union_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/module.amd.tmpl",
+    "$mojom_generator_root/generators/js_templates/module_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/struct_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/union_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/validation_macros.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm.cc.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm.h.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm.proto.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm_from_proto_macros.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm_macros.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm_to_proto_macros.tmpl",
+    "$mojom_generator_root/generators/mojolpm_templates/mojolpm_traits_specialization_macros.tmpl",
+    "$mojom_generator_root/generators/ts_templates/module_definition.tmpl",
+    "$mojom_generator_root/generators/ts_templates/mojom.tmpl",
+  ]
+  script = mojom_generator_script
+
+  inputs = jinja2_sources
+  outputs = [
+    "$target_gen_dir/cpp_templates.zip",
+    "$target_gen_dir/java_templates.zip",
+    "$target_gen_dir/mojolpm_templates.zip",
+    "$target_gen_dir/js_templates.zip",
+    "$target_gen_dir/ts_templates.zip",
+  ]
+  args = [
+    "-o",
+    rebase_path(target_gen_dir, root_build_dir),
+    "--use_bundled_pylibs",
+    "precompile",
+  ]
+}
diff --git a/utils/ipc/mojo/public/tools/bindings/README.md b/utils/ipc/mojo/public/tools/bindings/README.md
new file mode 100644
index 00000000..1a3d5c58
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/README.md
@@ -0,0 +1,816 @@
+# Mojom Interface Definition Language (IDL)
+This document is a subset of the [Mojo documentation](/mojo/README.md).
+
+[TOC]
+
+## Overview
+
+Mojom is the IDL for Mojo interfaces. Given a `.mojom` file, the
+[bindings
+generator](https://cs.chromium.org/chromium/src/mojo/public/tools/bindings/) can
+output bindings for any supported language: **C++**, **JavaScript**, or
+**Java**.
+
+For a trivial example consider the following hypothetical Mojom file we write to
+`//services/widget/public/mojom/frobinator.mojom`:
+
+```
+module widget.mojom;
+
+interface Frobinator {
+  Frobinate();
+};
+```
+
+This defines a single [interface](#Interfaces) named `Frobinator` in a
+[module](#Modules) named `widget.mojom` (and thus fully qualified in Mojom as
+`widget.mojom.Frobinator`.) Note that many interfaces and/or other types of
+definitions (structs, enums, *etc.*) may be included in a single Mojom file.
+
+If we add a corresponding GN target to
+`//services/widget/public/mojom/BUILD.gn`:
+
+```
+import("mojo/public/tools/bindings/mojom.gni")
+
+mojom("mojom") {
+  sources = [
+    "frobinator.mojom",
+  ]
+}
+```
+
+and then build this target:
+
+```
+ninja -C out/r services/widget/public/mojom
+```
+
+we'll find several generated sources in our output directory:
+
+```
+out/r/gen/services/widget/public/mojom/frobinator.mojom.cc
+out/r/gen/services/widget/public/mojom/frobinator.mojom.h
+out/r/gen/services/widget/public/mojom/frobinator.mojom-shared.h
+etc...
+```
+
+Each of these generated source modules includes a set of definitions
+representing the Mojom contents in C++. You can also build or depend on suffixed
+target names to get bindings for other languages. For example,
+
+```
+ninja -C out/r services/widget/public/mojom:mojom_js
+ninja -C out/r services/widget/public/mojom:mojom_java
+```
+
+would generate JavaScript and Java bindings respectively, in the same generated
+output directory.
+
+For more details regarding the generated
+outputs please see
+[documentation for individual target languages](#Generated-Code-For-Target-Languages).
+
+## Mojom Syntax
+
+Mojom IDL allows developers to define **structs**, **unions**, **interfaces**,
+**constants**, and **enums**, all within the context of a **module**. These
+definitions are used to generate code in the supported target languages at build
+time.
+
+Mojom files may **import** other Mojom files in order to reference their
+definitions.
+
+### Primitive Types
+Mojom supports a few basic data types which may be composed into structs or used
+for message parameters.
+
+| Type                          | Description
+|-------------------------------|-------------------------------------------------------|
+| `bool`                        | Boolean type (`true` or `false`.)
+| `int8`, `uint8`               | Signed or unsigned 8-bit integer.
+| `int16`, `uint16`             | Signed or unsigned 16-bit integer.
+| `int32`, `uint32`             | Signed or unsigned 32-bit integer.
+| `int64`, `uint64`             | Signed or unsigned 64-bit integer.
+| `float`, `double`             | 32- or 64-bit floating point number.
+| `string`                      | UTF-8 encoded string.
+| `array<T>`                    | Array of any Mojom type *T*; for example, `array<uint8>` or `array<array<string>>`.
+| `array<T, N>`                 | Fixed-length array of any Mojom type *T*. The parameter *N* must be an integral constant.
+| `map<S, T>`                   | Associated array maping values of type *S* to values of type *T*. *S* may be a `string`, `enum`, or numeric type.
+| `handle`                      | Generic Mojo handle. May be any type of handle, including a wrapped native platform handle.
+| `handle<message_pipe>`        | Generic message pipe handle.
+| `handle<shared_buffer>`       | Shared buffer handle.
+| `handle<data_pipe_producer>`  | Data pipe producer handle.
+| `handle<data_pipe_consumer>`  | Data pipe consumer handle.
+| `handle<platform>`            | A native platform/OS handle.
+| *`pending_remote<InterfaceType>`*             | Any user-defined Mojom interface type. This is sugar for a strongly-typed message pipe handle which should eventually be used to make outgoing calls on the interface.
+| *`pending_receiver<InterfaceType>`*            | A pending receiver for any user-defined Mojom interface type. This is sugar for a more strongly-typed message pipe handle which is expected to receive request messages and should therefore eventually be bound to an implementation of the interface.
+| *`pending_associated_remote<InterfaceType>`*  | An associated interface handle. See [Associated Interfaces](#Associated-Interfaces)
+| *`pending_associated_receiver<InterfaceType>`* | A pending associated receiver. See [Associated Interfaces](#Associated-Interfaces)
+| *T*?                          | An optional (nullable) value. Primitive numeric types (integers, floats, booleans, and enums) are not nullable. All other types are nullable.
+
+### Modules
+
+Every Mojom file may optionally specify a single **module** to which it belongs.
+
+This is used strictly for aggregaging all defined symbols therein within a
+common Mojom namespace. The specific impact this has on generated binidngs code
+varies for each target language. For example, if the following Mojom is used to
+generate bindings:
+
+```
+module business.stuff;
+
+interface MoneyGenerator {
+  GenerateMoney();
+};
+```
+
+Generated C++ bindings will define a class interface `MoneyGenerator` in the
+`business::stuff` namespace, while Java bindings will define an interface
+`MoneyGenerator` in the `org.chromium.business.stuff` package. JavaScript
+bindings at this time are unaffected by module declarations.
+
+**NOTE:** By convention in the Chromium codebase, **all** Mojom files should
+declare a module name with at least (and preferrably exactly) one top-level name
+as well as an inner `mojom` module suffix. *e.g.*, `chrome.mojom`,
+`business.mojom`, *etc.*
+
+This convention makes it easy to tell which symbols are generated by Mojom when
+reading non-Mojom code, and it also avoids namespace collisions in the fairly
+common scenario where you have a real C++ or Java `Foo` along with a
+corresponding Mojom `Foo` for its serialized representation.
+
+### Imports
+
+If your Mojom references definitions from other Mojom files, you must **import**
+those files. Import syntax is as follows:
+
+```
+import "services/widget/public/mojom/frobinator.mojom";
+```
+
+Import paths are always relative to the top-level directory.
+
+Note that circular imports are **not** supported.
+
+### Structs
+
+Structs are defined using the **struct** keyword, and they provide a way to
+group related fields together:
+
+``` cpp
+struct StringPair {
+  string first;
+  string second;
+};
+```
+
+Struct fields may be comprised of any of the types listed above in the
+[Primitive Types](#Primitive-Types) section.
+
+Default values may be specified as long as they are constant:
+
+``` cpp
+struct Request {
+  int32 id = -1;
+  string details;
+};
+```
+
+What follows is a fairly
+comprehensive example using the supported field types:
+
+``` cpp
+struct StringPair {
+  string first;
+  string second;
+};
+
+enum AnEnum {
+  YES,
+  NO
+};
+
+interface SampleInterface {
+  DoStuff();
+};
+
+struct AllTheThings {
+  // Note that these types can never be marked nullable!
+  bool boolean_value;
+  int8 signed_8bit_value = 42;
+  uint8 unsigned_8bit_value;
+  int16 signed_16bit_value;
+  uint16 unsigned_16bit_value;
+  int32 signed_32bit_value;
+  uint32 unsigned_32bit_value;
+  int64 signed_64bit_value;
+  uint64 unsigned_64bit_value;
+  float float_value_32bit;
+  double float_value_64bit;
+  AnEnum enum_value = AnEnum.YES;
+
+  // Strings may be nullable.
+  string? maybe_a_string_maybe_not;
+
+  // Structs may contain other structs. These may also be nullable.
+  StringPair some_strings;
+  StringPair? maybe_some_more_strings;
+
+  // In fact structs can also be nested, though in practice you must always make
+  // such fields nullable -- otherwise messages would need to be infinitely long
+  // in order to pass validation!
+  AllTheThings? more_things;
+
+  // Arrays may be templated over any Mojom type, and are always nullable:
+  array<int32> numbers;
+  array<int32>? maybe_more_numbers;
+
+  // Arrays of arrays of arrays... are fine.
+  array<array<array<AnEnum>>> this_works_but_really_plz_stop;
+
+  // The element type may be nullable if it's a type which is allowed to be
+  // nullable.
+  array<AllTheThings?> more_maybe_things;
+
+  // Fixed-size arrays get some extra validation on the receiving end to ensure
+  // that the correct number of elements is always received.
+  array<uint64, 2> uuid;
+
+  // Maps follow many of the same rules as arrays. Key types may be any
+  // non-handle, non-collection type, and value types may be any supported
+  // struct field type. Maps may also be nullable.
+  map<string, int32> one_map;
+  map<AnEnum, string>? maybe_another_map;
+  map<StringPair, AllTheThings?>? maybe_a_pretty_weird_but_valid_map;
+  map<StringPair, map<int32, array<map<string, string>?>?>?> ridiculous;
+
+  // And finally, all handle types are valid as struct fields and may be
+  // nullable. Note that interfaces and interface requests (the "Foo" and
+  // "Foo&" type syntax respectively) are just strongly-typed message pipe
+  // handles.
+  handle generic_handle;
+  handle<data_pipe_consumer> reader;
+  handle<data_pipe_producer>? maybe_writer;
+  handle<shared_buffer> dumping_ground;
+  handle<message_pipe> raw_message_pipe;
+  pending_remote<SampleInterface>? maybe_a_sample_interface_client_pipe;
+  pending_receiver<SampleInterface> non_nullable_sample_pending_receiver;
+  pending_receiver<SampleInterface>? nullable_sample_pending_receiver;
+  pending_associated_remote<SampleInterface> associated_interface_client;
+  pending_associated_receiver<SampleInterface> associated_pending_receiver;
+  pending_associated_receiver<SampleInterface>? maybe_another_pending_receiver;
+};
+```
+
+For details on how all of these different types translate to usable generated
+code, see
+[documentation for individual target languages](#Generated-Code-For-Target-Languages).
+
+### Unions
+
+Mojom supports tagged unions using the **union** keyword. A union is a
+collection of fields which may taken the value of any single one of those fields
+at a time. Thus they provide a way to represent a variant value type while
+minimizing storage requirements.
+
+Union fields may be of any type supported by [struct](#Structs) fields. For
+example:
+
+```cpp
+union ExampleUnion {
+  string str;
+  StringPair pair;
+  int64 id;
+  array<uint64, 2> guid;
+  SampleInterface iface;
+};
+```
+
+For details on how unions like this translate to generated bindings code, see
+[documentation for individual target languages](#Generated-Code-For-Target-Languages).
+
+### Enumeration Types
+
+Enumeration types may be defined using the **enum** keyword either directly
+within a module or nested within the namespace of some struct or interface:
+
+```
+module business.mojom;
+
+enum Department {
+  SALES = 0,
+  DEV,
+};
+
+struct Employee {
+  enum Type {
+    FULL_TIME,
+    PART_TIME,
+  };
+
+  Type type;
+  // ...
+};
+```
+
+Similar to C-style enums, individual values may be explicitly assigned within an
+enum definition. By default, values are based at zero and increment by
+1 sequentially.
+
+The effect of nested definitions on generated bindings varies depending on the
+target language. See [documentation for individual target languages](#Generated-Code-For-Target-Languages)
+
+### Constants
+
+Constants may be defined using the **const** keyword either directly within a
+module or nested within the namespace of some struct or interface:
+
+```
+module business.mojom;
+
+const string kServiceName = "business";
+
+struct Employee {
+  const uint64 kInvalidId = 0;
+
+  enum Type {
+    FULL_TIME,
+    PART_TIME,
+  };
+
+  uint64 id = kInvalidId;
+  Type type;
+};
+```
+
+The effect of nested definitions on generated bindings varies depending on the
+target language. See [documentation for individual target languages](#Generated-Code-For-Target-Languages)
+
+### Interfaces
+
+An **interface** is a logical bundle of parameterized request messages. Each
+request message may optionally define a parameterized response message. Here's
+an example to define an interface `Foo` with various kinds of requests:
+
+```
+interface Foo {
+  // A request which takes no arguments and expects no response.
+  MyMessage();
+
+  // A request which has some arguments and expects no response.
+  MyOtherMessage(string name, array<uint8> bytes);
+
+  // A request which expects a single-argument response.
+  MyMessageWithResponse(string command) => (bool success);
+
+  // A request which expects a response with multiple arguments.
+  MyMessageWithMoarResponse(string a, string b) => (int8 c, int8 d);
+};
+```
+
+Anything which is a valid struct field type (see [Structs](#Structs)) is also a
+valid request or response argument type. The type notation is the same for both.
+
+### Attributes
+
+Mojom definitions may have their meaning altered by **attributes**, specified
+with a syntax similar to Java or C# attributes. There are a handle of
+interesting attributes supported today.
+
+**`[Sync]`**
+:   The `Sync` attribute may be specified for any interface method which expects
+    a response. This makes it so that callers of the method can wait
+    synchronously for a response. See
+    [Synchronous Calls](/mojo/public/cpp/bindings/README.md#Synchronous-Calls)
+    in the C++ bindings documentation. Note that sync methods are only actually
+    synchronous when called from C++.
+
+**`[Extensible]`**
+:   The `Extensible` attribute may be specified for any enum definition. This
+    essentially disables builtin range validation when receiving values of the
+    enum type in a message, allowing older bindings to tolerate unrecognized
+    values from newer versions of the enum.
+
+**`[Native]`**
+:   The `Native` attribute may be specified for an empty struct declaration to
+    provide a nominal bridge between Mojo IPC and legacy `IPC::ParamTraits` or
+    `IPC_STRUCT_TRAITS*` macros.
+    See
+    [Repurposing Legacy IPC Traits](/docs/mojo_ipc_conversion.md#repurposing-and-invocations)
+    for more details. Note support for this attribute is strictly limited to C++
+    bindings generation.
+
+**`[MinVersion=N]`**
+:   The `MinVersion` attribute is used to specify the version at which a given
+    field, enum value, interface method, or method parameter was introduced.
+    See [Versioning](#Versioning) for more details.
+
+**`[Stable]`**
+:   The `Stable` attribute specifies that a given mojom type or interface
+    definition can be considered stable over time, meaning it is safe to use for
+    things like persistent storage or communication between independent
+    version-skewed binaries. Stable definitions may only depend on builtin mojom
+    types or other stable definitions, and changes to such definitions MUST
+    preserve backward-compatibility through appropriate use of versioning.
+    Backward-compatibility of changes is enforced in the Chromium tree using a
+    strict presubmit check. See [Versioning](#Versioning) for more details on
+    backward-compatibility constraints.
+
+**`[EnableIf=value]`**
+:   The `EnableIf` attribute is used to conditionally enable definitions when
+    the mojom is parsed. If the `mojom` target in the GN file does not include
+    the matching `value` in the list of `enabled_features`, the definition
+    will be disabled. This is useful for mojom definitions that only make
+    sense on one platform. Note that the `EnableIf` attribute can only be set
+    once per definition.
+
+## Generated Code For Target Languages
+
+When the bindings generator successfully processes an input Mojom file, it emits
+corresponding code for each supported target language. For more details on how
+Mojom concepts translate to a given target langauge, please refer to the
+bindings API documentation for that language:
+
+* [C++ Bindings](/mojo/public/cpp/bindings/README.md)
+* [JavaScript Bindings](/mojo/public/js/README.md)
+* [Java Bindings](/mojo/public/java/bindings/README.md)
+
+## Message Validation
+
+Regardless of target language, all interface messages are validated during
+deserialization before they are dispatched to a receiving implementation of the
+interface. This helps to ensure consitent validation across interfaces without
+leaving the burden to developers and security reviewers every time a new message
+is added.
+
+If a message fails validation, it is never dispatched. Instead a **connection
+error** is raised on the binding object (see
+[C++ Connection Errors](/mojo/public/cpp/bindings/README.md#Connection-Errors),
+[Java Connection Errors](/mojo/public/java/bindings/README.md#Connection-Errors),
+or
+[JavaScript Connection Errors](/mojo/public/js/README.md#Connection-Errors) for
+details.)
+
+Some baseline level of validation is done automatically for primitive Mojom
+types.
+
+### Non-Nullable Objects
+
+Mojom fields or parameter values (*e.g.*, structs, interfaces, arrays, *etc.*)
+may be marked nullable in Mojom definitions (see
+[Primitive Types](#Primitive-Types).) If a field or parameter is **not** marked
+nullable but a message is received with a null value in its place, that message
+will fail validation.
+
+### Enums
+
+Enums declared in Mojom are automatically validated against the range of legal
+values. For example if a Mojom declares the enum:
+
+``` cpp
+enum AdvancedBoolean {
+  TRUE = 0,
+  FALSE = 1,
+  FILE_NOT_FOUND = 2,
+};
+```
+
+and a message is received with the integral value 3 (or anything other than 0,
+1, or 2) in place of some `AdvancedBoolean` field or parameter, the message will
+fail validation.
+
+*** note
+NOTE: It's possible to avoid this type of validation error by explicitly marking
+an enum as [Extensible](#Attributes) if you anticipate your enum being exchanged
+between two different versions of the binding interface. See
+[Versioning](#Versioning).
+***
+
+### Other failures
+
+There are a  host of internal validation errors that may occur when a malformed
+message is received, but developers should not be concerned with these
+specifically; in general they can only result from internal bindings bugs,
+compromised processes, or some remote endpoint making a dubious effort to
+manually encode their own bindings messages.
+
+### Custom Validation
+
+It's also possible for developers to define custom validation logic for specific
+Mojom struct types by exploiting the
+[type mapping](/mojo/public/cpp/bindings/README.md#Type-Mapping) system for C++
+bindings. Messages rejected by custom validation logic trigger the same
+validation failure behavior as the built-in type validation routines.
+
+## Associated Interfaces
+
+As mentioned in the [Primitive Types](#Primitive-Types) section above, pending_remote
+and pending_receiver fields and parameters may be marked as `associated`. This
+essentially means that they are piggy-backed on some other interface's message
+pipe.
+
+Because individual interface message pipes operate independently there can be no
+relative ordering guarantees among them. Associated interfaces are useful when
+one interface needs to guarantee strict FIFO ordering with respect to one or
+more other interfaces, as they allow interfaces to share a single pipe.
+
+Currently associated interfaces are only supported in generated C++ bindings.
+See the documentation for
+[C++ Associated Interfaces](/mojo/public/cpp/bindings/README.md#Associated-Interfaces).
+
+## Versioning
+
+### Overview
+
+*** note
+**NOTE:** You don't need to worry about versioning if you don't care about
+backwards compatibility. Specifically, all parts of Chrome are updated
+atomically today and there is not yet any possibility of any two Chrome
+processes communicating with two different versions of any given Mojom
+interface.
+***
+
+Services extend their interfaces to support new features over time, and clients
+want to use those new features when they are available. If services and clients
+are not updated at the same time, it's important for them to be able to
+communicate with each other using different snapshots (versions) of their
+interfaces.
+
+This document shows how to extend Mojom interfaces in a backwards-compatible
+way. Changing interfaces in a non-backwards-compatible way is not discussed,
+because in that case communication between different interface versions is
+impossible anyway.
+
+### Versioned Structs
+
+You can use the `MinVersion` [attribute](#Attributes) to indicate from which
+version a struct field is introduced. Assume you have the following struct:
+
+``` cpp
+struct Employee {
+  uint64 employee_id;
+  string name;
+};
+```
+
+and you would like to add a birthday field. You can do:
+
+``` cpp
+struct Employee {
+  uint64 employee_id;
+  string name;
+  [MinVersion=1] Date? birthday;
+};
+```
+
+By default, fields belong to version 0. New fields must be appended to the
+struct definition (*i.e*., existing fields must not change **ordinal value**)
+with the `MinVersion` attribute set to a number greater than any previous
+existing versions.
+
+*** note
+**NOTE:** do not change existing fields in versioned structs, as this is
+not backwards-compatible. Instead, rename the old field to make its
+deprecation clear and add a new field with the new version number.
+***
+
+**Ordinal value** refers to the relative positional layout of a struct's fields
+(and an interface's methods) when encoded in a message. Implicitly, ordinal
+numbers are assigned to fields according to lexical position. In the example
+above, `employee_id` has an ordinal value of 0 and `name` has an ordinal value
+of 1.
+
+Ordinal values can be specified explicitly using `**@**` notation, subject to
+the following hard constraints:
+
+* For any given struct or interface, if any field or method explicitly specifies
+    an ordinal value, all fields or methods must explicitly specify an ordinal
+    value.
+* For an *N*-field struct or *N*-method interface, the set of explicitly
+    assigned ordinal values must be limited to the range *[0, N-1]*. Interfaces
+    should include placeholder methods to fill the ordinal positions of removed
+    methods (for example "Unused_Message_7@7()" or "RemovedMessage@42()", etc).
+
+You may reorder fields, but you must ensure that the ordinal values of existing
+fields remain unchanged. For example, the following struct remains
+backwards-compatible:
+
+``` cpp
+struct Employee {
+  uint64 employee_id@0;
+  [MinVersion=1] Date? birthday@2;
+  string name@1;
+};
+```
+
+*** note
+**NOTE:** Newly added fields of Mojo object or handle types MUST be nullable.
+See [Primitive Types](#Primitive-Types).
+***
+
+### Versioned Interfaces
+
+There are two dimensions on which an interface can be extended
+
+**Appending New Parameters To Existing Methods**
+:   Parameter lists are treated as structs internally, so all the rules of
+    versioned structs apply to method parameter lists. The only difference is
+    that the version number is scoped to the whole interface rather than to any
+    individual parameter list.
+
+    Please note that adding a response to a message which did not previously
+    expect a response is a not a backwards-compatible change.
+
+**Appending New Methods**
+:   Similarly, you can reorder methods with explicit ordinal values as long as
+    the ordinal values of existing methods are unchanged.
+
+For example:
+
+``` cpp
+// Old version:
+interface HumanResourceDatabase {
+  AddEmployee(Employee employee) => (bool success);
+  QueryEmployee(uint64 id) => (Employee? employee);
+};
+
+// New version:
+interface HumanResourceDatabase {
+  AddEmployee(Employee employee) => (bool success);
+
+  QueryEmployee(uint64 id, [MinVersion=1] bool retrieve_finger_print)
+      => (Employee? employee,
+          [MinVersion=1] array<uint8>? finger_print);
+
+  [MinVersion=1]
+  AttachFingerPrint(uint64 id, array<uint8> finger_print)
+      => (bool success);
+};
+```
+
+Similar to [versioned structs](#Versioned-Structs), when you pass the parameter
+list of a request or response method to a destination using an older version of
+an interface, unrecognized fields are silently discarded. However, if the method
+call itself is not recognized, it is considered a validation error and the
+receiver will close its end of the interface pipe. For example, if a client on
+version 1 of the above interface sends an `AttachFingerPrint` request to an
+implementation of version 0, the client will be disconnected.
+
+Bindings target languages that support versioning expose means to query or
+assert the remote version from a client handle (*e.g.*, an
+`mojo::Remote<T>` in C++ bindings.)
+
+See
+[C++ Versioning Considerations](/mojo/public/cpp/bindings/README.md#Versioning-Considerations)
+and
+[Java Versioning Considerations](/mojo/public/java/bindings/README.md#Versioning-Considerations)
+
+### Versioned Enums
+
+**By default, enums are non-extensible**, which means that generated message
+validation code does not expect to see new values in the future. When an unknown
+value is seen for a non-extensible enum field or parameter, a validation error
+is raised.
+
+If you want an enum to be extensible in the future, you can apply the
+`[Extensible]` [attribute](#Attributes):
+
+``` cpp
+[Extensible]
+enum Department {
+  SALES,
+  DEV,
+};
+```
+
+And later you can extend this enum without breaking backwards compatibility:
+
+``` cpp
+[Extensible]
+enum Department {
+  SALES,
+  DEV,
+  [MinVersion=1] RESEARCH,
+};
+```
+
+*** note
+**NOTE:** For versioned enum definitions, the use of a `[MinVersion]` attribute
+is strictly for documentation purposes. It has no impact on the generated code.
+***
+
+With extensible enums, bound interface implementations may receive unknown enum
+values and will need to deal with them gracefully. See
+[C++ Versioning Considerations](/mojo/public/cpp/bindings/README.md#Versioning-Considerations)
+for details.
+
+## Grammar Reference
+
+Below is the (BNF-ish) context-free grammar of the Mojom language:
+
+```
+MojomFile = StatementList
+StatementList = Statement StatementList | Statement
+Statement = ModuleStatement | ImportStatement | Definition
+
+ModuleStatement = AttributeSection "module" Identifier ";"
+ImportStatement = "import" StringLiteral ";"
+Definition = Struct Union Interface Enum Const
+
+AttributeSection = <empty> | "[" AttributeList "]"
+AttributeList = <empty> | NonEmptyAttributeList
+NonEmptyAttributeList = Attribute
+                      | Attribute "," NonEmptyAttributeList
+Attribute = Name
+          | Name "=" Name
+          | Name "=" Literal
+
+Struct = AttributeSection "struct" Name "{" StructBody "}" ";"
+       | AttributeSection "struct" Name ";"
+StructBody = <empty>
+           | StructBody Const
+           | StructBody Enum
+           | StructBody StructField
+StructField = AttributeSection TypeSpec Name Ordinal Default ";"
+
+Union = AttributeSection "union" Name "{" UnionBody "}" ";"
+UnionBody = <empty> | UnionBody UnionField
+UnionField = AttributeSection TypeSpec Name Ordinal ";"
+
+Interface = AttributeSection "interface" Name "{" InterfaceBody "}" ";"
+InterfaceBody = <empty>
+              | InterfaceBody Const
+              | InterfaceBody Enum
+              | InterfaceBody Method
+Method = AttributeSection Name Ordinal "(" ParamterList ")" Response ";"
+ParameterList = <empty> | NonEmptyParameterList
+NonEmptyParameterList = Parameter
+                      | Parameter "," NonEmptyParameterList
+Parameter = AttributeSection TypeSpec Name Ordinal
+Response = <empty> | "=>" "(" ParameterList ")"
+
+TypeSpec = TypeName "?" | TypeName
+TypeName = BasicTypeName
+         | Array
+         | FixedArray
+         | Map
+         | InterfaceRequest
+BasicTypeName = Identifier | "associated" Identifier | HandleType | NumericType
+NumericType = "bool" | "int8" | "uint8" | "int16" | "uint16" | "int32"
+            | "uint32" | "int64" | "uint64" | "float" | "double"
+HandleType = "handle" | "handle" "<" SpecificHandleType ">"
+SpecificHandleType = "message_pipe"
+                   | "shared_buffer"
+                   | "data_pipe_consumer"
+                   | "data_pipe_producer"
+                   | "platform"
+Array = "array" "<" TypeSpec ">"
+FixedArray = "array" "<" TypeSpec "," IntConstDec ">"
+Map = "map" "<" Identifier "," TypeSpec ">"
+InterfaceRequest = Identifier "&" | "associated" Identifier "&"
+
+Ordinal = <empty> | OrdinalValue
+
+Default = <empty> | "=" Constant
+
+Enum = AttributeSection "enum" Name "{" NonEmptyEnumValueList "}" ";"
+     | AttributeSection "enum" Name "{" NonEmptyEnumValueList "," "}" ";"
+NonEmptyEnumValueList = EnumValue | NonEmptyEnumValueList "," EnumValue
+EnumValue = AttributeSection Name
+          | AttributeSection Name "=" Integer
+          | AttributeSection Name "=" Identifier
+
+Const = "const" TypeSpec Name "=" Constant ";"
+
+Constant = Literal | Identifier ";"
+
+Identifier = Name | Name "." Identifier
+
+Literal = Integer | Float | "true" | "false" | "default" | StringLiteral
+
+Integer = IntConst | "+" IntConst | "-" IntConst
+IntConst = IntConstDec | IntConstHex
+
+Float = FloatConst | "+" FloatConst | "-" FloatConst
+
+; The rules below are for tokens matched strictly according to the given regexes
+
+Identifier = /[a-zA-Z_][0-9a-zA-Z_]*/
+IntConstDec = /0|(1-9[0-9]*)/
+IntConstHex = /0[xX][0-9a-fA-F]+/
+OrdinalValue = /@(0|(1-9[0-9]*))/
+FloatConst = ... # Imagine it's close enough to C-style float syntax.
+StringLiteral = ... # Imagine it's close enough to C-style string literals, including escapes.
+```
+
+## Additional Documentation
+
+[Mojom Message Format](https://docs.google.com/document/d/13pv9cFh5YKuBggDBQ1-AL8VReF-IYpFOFpRfvWFrwio/edit)
+:    Describes the wire format used by Mojo bindings interfaces over message
+     pipes.
+
+[Input Format of Mojom Message Validation Tests](https://docs.google.com/document/d/1-y-2IYctyX2NPaLxJjpJfzVNWCC2SR2MJAD9MpIytHQ/edit)
+:    Describes a text format used to facilitate bindings message validation
+     tests.
diff --git a/utils/ipc/mojo/public/tools/bindings/chromium_bindings_configuration.gni b/utils/ipc/mojo/public/tools/bindings/chromium_bindings_configuration.gni
new file mode 100644
index 00000000..d8a13874
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/chromium_bindings_configuration.gni
@@ -0,0 +1,51 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+_typemap_imports = [
+  "//chrome/chrome_cleaner/mojom/typemaps/typemaps.gni",
+  "//chrome/common/importer/typemaps.gni",
+  "//chrome/common/media_router/mojom/typemaps.gni",
+  "//chrome/typemaps.gni",
+  "//chromecast/typemaps.gni",
+  "//chromeos/typemaps.gni",
+  "//chromeos/components/multidevice/mojom/typemaps.gni",
+  "//chromeos/services/cros_healthd/public/mojom/typemaps.gni",
+  "//chromeos/services/device_sync/public/mojom/typemaps.gni",
+  "//chromeos/services/network_config/public/mojom/typemaps.gni",
+  "//chromeos/services/secure_channel/public/mojom/typemaps.gni",
+  "//components/arc/mojom/typemaps.gni",
+  "//components/chromeos_camera/common/typemaps.gni",
+  "//components/services/storage/public/cpp/filesystem/typemaps.gni",
+  "//components/sync/mojom/typemaps.gni",
+  "//components/typemaps.gni",
+  "//content/browser/typemaps.gni",
+  "//content/public/common/typemaps.gni",
+  "//sandbox/mac/mojom/typemaps.gni",
+  "//services/media_session/public/cpp/typemaps.gni",
+  "//services/proxy_resolver/public/cpp/typemaps.gni",
+  "//services/resource_coordinator/public/cpp/typemaps.gni",
+  "//services/service_manager/public/cpp/typemaps.gni",
+  "//services/tracing/public/mojom/typemaps.gni",
+]
+
+_typemaps = []
+foreach(typemap_import, _typemap_imports) {
+  # Avoid reassignment error by assigning to empty scope first.
+  _imported = {
+  }
+  _imported = read_file(typemap_import, "scope")
+  _typemaps += _imported.typemaps
+}
+
+typemaps = []
+foreach(typemap, _typemaps) {
+  typemaps += [
+    {
+      filename = typemap
+      config = read_file(typemap, "scope")
+    },
+  ]
+}
+
+component_macro_suffix = ""
diff --git a/utils/ipc/mojo/public/tools/bindings/compile_typescript.py b/utils/ipc/mojo/public/tools/bindings/compile_typescript.py
new file mode 100644
index 00000000..a978901b
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/compile_typescript.py
@@ -0,0 +1,27 @@
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import sys
+import argparse
+
+_HERE_PATH = os.path.dirname(__file__)
+_SRC_PATH = os.path.normpath(os.path.join(_HERE_PATH, '..', '..', '..', '..'))
+
+sys.path.append(os.path.join(_SRC_PATH, 'third_party', 'node'))
+import node
+import node_modules
+
+def main(argv):
+  parser = argparse.ArgumentParser()
+  parser.add_argument('--tsconfig_path', required=True)
+  args = parser.parse_args(argv)
+
+  result = node.RunNode([node_modules.PathToTypescript()] +
+                        ['--project', args.tsconfig_path])
+  if len(result) != 0:
+    raise RuntimeError('Failed to compile Typescript: \n%s' % result)
+
+if __name__ == '__main__':
+  main(sys.argv[1:])
diff --git a/utils/ipc/mojo/public/tools/bindings/concatenate-files.py b/utils/ipc/mojo/public/tools/bindings/concatenate-files.py
new file mode 100755
index 00000000..48bc66fd
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/concatenate-files.py
@@ -0,0 +1,54 @@
+#!/usr/bin/env python
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# This utility concatenates several files into one. On Unix-like systems
+# it is equivalent to:
+#   cat file1 file2 file3 ...files... > target
+#
+# The reason for writing a separate utility is that 'cat' is not available
+# on all supported build platforms, but Python is, and hence this provides
+# us with an easy and uniform way of doing this on all platforms.
+
+# for py2/py3 compatibility
+from __future__ import print_function
+
+import optparse
+
+
+def Concatenate(filenames):
+  """Concatenate files.
+
+  Args:
+    files: Array of file names.
+           The last name is the target; all earlier ones are sources.
+
+  Returns:
+    True, if the operation was successful.
+  """
+  if len(filenames) < 2:
+    print("An error occurred generating %s:\nNothing to do." % filenames[-1])
+    return False
+
+  try:
+    with open(filenames[-1], "wb") as target:
+      for filename in filenames[:-1]:
+        with open(filename, "rb") as current:
+          target.write(current.read())
+    return True
+  except IOError as e:
+    print("An error occurred when writing %s:\n%s" % (filenames[-1], e))
+    return False
+
+
+def main():
+  parser = optparse.OptionParser()
+  parser.set_usage("""Concatenate several files into one.
+      Equivalent to: cat file1 ... > target.""")
+  (_options, args) = parser.parse_args()
+  exit(0 if Concatenate(args) else 1)
+
+
+if __name__ == "__main__":
+  main()
diff --git a/utils/ipc/mojo/public/tools/bindings/concatenate_and_replace_closure_exports.py b/utils/ipc/mojo/public/tools/bindings/concatenate_and_replace_closure_exports.py
new file mode 100755
index 00000000..be8985ce
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/concatenate_and_replace_closure_exports.py
@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+# Copyright 2018 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Simple utility which concatenates a set of files into a single output file
+while also stripping any goog.provide or goog.require lines. This allows us to
+provide a very primitive sort of "compilation" without any extra toolchain
+support and without having to modify otherwise compilable sources in the tree
+which use these directives.
+
+goog.provide lines are replaced with an equivalent invocation of
+mojo.internal.exportModule, which accomplishes essentially the same thing in an
+uncompiled context. A singular exception is made for the 'mojo.internal' export,
+which is instead replaced with an inlined assignment to initialize the
+namespace.
+"""
+
+from __future__ import print_function
+
+import optparse
+import re
+
+
+_MOJO_INTERNAL_MODULE_NAME = "mojo.internal"
+_MOJO_EXPORT_MODULE_SYMBOL = "mojo.internal.exportModule"
+
+
+def FilterLine(filename, line, output):
+  if line.startswith("goog.require"):
+    return
+
+  if line.startswith("goog.provide"):
+    match = re.match("goog.provide\('([^']+)'\);", line)
+    if not match:
+      print("Invalid goog.provide line in %s:\n%s" % (filename, line))
+      exit(1)
+
+    module_name = match.group(1)
+    if module_name == _MOJO_INTERNAL_MODULE_NAME:
+      output.write("self.mojo = { internal: {} };")
+    else:
+      output.write("%s('%s');\n" % (_MOJO_EXPORT_MODULE_SYMBOL, module_name))
+    return
+
+  output.write(line)
+
+def ConcatenateAndReplaceExports(filenames):
+  if (len(filenames) < 2):
+    print("At least two filenames (one input and the output) are required.")
+    return False
+
+  try:
+    with open(filenames[-1], "w") as target:
+      for filename in filenames[:-1]:
+        with open(filename, "r") as current:
+          for line in current.readlines():
+            FilterLine(filename, line, target)
+    return True
+  except IOError as e:
+    print("Error generating %s\n: %s" % (filenames[-1], e))
+    return False
+
+def main():
+  parser = optparse.OptionParser()
+  parser.set_usage("""file1 [file2...] outfile
+    Concatenate several files into one, stripping Closure provide and
+    require directives along the way.""")
+  (_, args) = parser.parse_args()
+  exit(0 if ConcatenateAndReplaceExports(args) else 1)
+
+if __name__ == "__main__":
+  main()
diff --git a/utils/ipc/mojo/public/tools/bindings/format_typemap_generator_args.py b/utils/ipc/mojo/public/tools/bindings/format_typemap_generator_args.py
new file mode 100755
index 00000000..7ac4af5f
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/format_typemap_generator_args.py
@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from __future__ import print_function
+
+import sys
+
+# This utility converts mojom dependencies into their corresponding typemap
+# paths and formats them to be consumed by generate_type_mappings.py.
+
+
+def FormatTypemap(typemap_filename):
+  # A simple typemap is valid Python with a minor alteration.
+  with open(typemap_filename) as f:
+    typemap_content = f.read().replace('=\n', '=')
+  typemap = {}
+  exec typemap_content in typemap
+
+  for header in typemap.get('public_headers', []):
+    yield 'public_headers=%s' % header
+  for header in typemap.get('traits_headers', []):
+    yield 'traits_headers=%s' % header
+  for header in typemap.get('type_mappings', []):
+    yield 'type_mappings=%s' % header
+
+
+def main():
+  typemaps = sys.argv[1:]
+  print(' '.join('--start-typemap %s' % ' '.join(FormatTypemap(typemap))
+                 for typemap in typemaps))
+
+
+if __name__ == '__main__':
+  sys.exit(main())
diff --git a/utils/ipc/mojo/public/tools/bindings/gen_data_files_list.py b/utils/ipc/mojo/public/tools/bindings/gen_data_files_list.py
new file mode 100644
index 00000000..79c9e50e
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/gen_data_files_list.py
@@ -0,0 +1,52 @@
+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Generates a list of all files in a directory.
+
+This script takes in a directory and an output file name as input.
+It then reads the directory and creates a list of all file names
+in that directory.  The list is written to the output file.
+There is also an option to pass in '-p' or '--pattern'
+which will check each file name against a regular expression
+pattern that is passed in.  Only files which match the regex
+will be written to the list.
+"""
+
+from __future__ import print_function
+
+import os
+import re
+import sys
+
+from cStringIO import StringIO
+from optparse import OptionParser
+
+sys.path.insert(
+    0,
+    os.path.join(
+        os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "mojom"))
+
+from mojom.generate.generator import WriteFile
+
+
+def main():
+  parser = OptionParser()
+  parser.add_option('-d', '--directory', help='Read files from DIRECTORY')
+  parser.add_option('-o', '--output', help='Write list to FILE')
+  parser.add_option('-p',
+                    '--pattern',
+                    help='Only reads files that name matches PATTERN',
+                    default=".")
+  (options, _) = parser.parse_args()
+  pattern = re.compile(options.pattern)
+  files = [f for f in os.listdir(options.directory) if pattern.match(f)]
+
+  stream = StringIO()
+  for f in files:
+    print(f, file=stream)
+
+  WriteFile(stream.getvalue(), options.output)
+  stream.close()
+
+if __name__ == '__main__':
+  sys.exit(main())
diff --git a/utils/ipc/mojo/public/tools/bindings/generate_type_mappings.py b/utils/ipc/mojo/public/tools/bindings/generate_type_mappings.py
new file mode 100755
index 00000000..64ca048f
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/generate_type_mappings.py
@@ -0,0 +1,187 @@
+#!/usr/bin/env python
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Generates a JSON typemap from its command-line arguments and dependencies.
+
+Each typemap should be specified in an command-line argument of the form
+key=value, with an argument of "--start-typemap" preceding each typemap.
+
+For example,
+generate_type_mappings.py --output=foo.typemap --start-typemap \\
+    public_headers=foo.h traits_headers=foo_traits.h \\
+    type_mappings=mojom.Foo=FooImpl
+
+generates a foo.typemap containing
+{
+  "c++": {
+    "mojom.Foo": {
+      "typename": "FooImpl",
+      "traits_headers": [
+        "foo_traits.h"
+      ],
+      "public_headers": [
+        "foo.h"
+      ]
+    }
+  }
+}
+
+Then,
+generate_type_mappings.py --dependency foo.typemap --output=bar.typemap \\
+    --start-typemap public_headers=bar.h traits_headers=bar_traits.h \\
+    type_mappings=mojom.Bar=BarImpl
+
+generates a bar.typemap containing
+{
+  "c++": {
+    "mojom.Bar": {
+      "typename": "BarImpl",
+      "traits_headers": [
+        "bar_traits.h"
+      ],
+      "public_headers": [
+        "bar.h"
+      ]
+    },
+    "mojom.Foo": {
+      "typename": "FooImpl",
+      "traits_headers": [
+        "foo_traits.h"
+      ],
+      "public_headers": [
+        "foo.h"
+      ]
+    }
+  }
+}
+"""
+
+import argparse
+import json
+import os
+import re
+import sys
+
+sys.path.insert(
+    0,
+    os.path.join(
+        os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "mojom"))
+
+from mojom.generate.generator import WriteFile
+
+def ReadTypemap(path):
+  with open(path) as f:
+    return json.load(f)['c++']
+
+
+def ParseTypemapArgs(args):
+  typemaps = [s for s in '\n'.join(args).split('--start-typemap\n') if s]
+  result = {}
+  for typemap in typemaps:
+    result.update(ParseTypemap(typemap))
+  return result
+
+
+def LoadCppTypemapConfig(path):
+  configs = {}
+  with open(path) as f:
+    for config in json.load(f):
+      for entry in config['types']:
+        configs[entry['mojom']] = {
+            'typename': entry['cpp'],
+            'public_headers': config.get('traits_headers', []),
+            'traits_headers': config.get('traits_private_headers', []),
+            'copyable_pass_by_value': entry.get('copyable_pass_by_value',
+                                                False),
+            'force_serialize': entry.get('force_serialize', False),
+            'hashable': entry.get('hashable', False),
+            'move_only': entry.get('move_only', False),
+            'nullable_is_same_type': entry.get('nullable_is_same_type', False),
+            'non_copyable_non_movable': False,
+        }
+  return configs
+
+
+def ParseTypemap(typemap):
+  values = {'type_mappings': [], 'public_headers': [], 'traits_headers': []}
+  for line in typemap.split('\n'):
+    if not line:
+      continue
+    key, _, value = line.partition('=')
+    values[key].append(value.lstrip('/'))
+  result = {}
+  mapping_pattern = \
+      re.compile(r"""^([^=]+)           # mojom type
+                     =
+                     ([^[]+)            # native type
+                     (?:\[([^]]+)\])?$  # optional attribute in square brackets
+                 """, re.X)
+  for typename in values['type_mappings']:
+    match_result = mapping_pattern.match(typename)
+    assert match_result, (
+        "Cannot parse entry in the \"type_mappings\" section: %s" % typename)
+
+    mojom_type = match_result.group(1)
+    native_type = match_result.group(2)
+    attributes = []
+    if match_result.group(3):
+      attributes = match_result.group(3).split(',')
+
+    assert mojom_type not in result, (
+        "Cannot map multiple native types (%s, %s) to the same mojom type: %s" %
+        (result[mojom_type]['typename'], native_type, mojom_type))
+
+    result[mojom_type] = {
+        'public_headers': values['public_headers'],
+        'traits_headers': values['traits_headers'],
+        'typename': native_type,
+
+        # Attributes supported for individual mappings.
+        'copyable_pass_by_value': 'copyable_pass_by_value' in attributes,
+        'force_serialize': 'force_serialize' in attributes,
+        'hashable': 'hashable' in attributes,
+        'move_only': 'move_only' in attributes,
+        'non_copyable_non_movable': 'non_copyable_non_movable' in attributes,
+        'nullable_is_same_type': 'nullable_is_same_type' in attributes,
+    }
+  return result
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description=__doc__,
+      formatter_class=argparse.RawDescriptionHelpFormatter)
+  parser.add_argument(
+      '--dependency',
+      type=str,
+      action='append',
+      default=[],
+      help=('A path to another JSON typemap to merge into the output. '
+            'This may be repeated to merge multiple typemaps.'))
+  parser.add_argument(
+      '--cpp-typemap-config',
+      type=str,
+      action='store',
+      dest='cpp_config_path',
+      help=('A path to a single JSON-formatted typemap config as emitted by'
+            'GN when processing a mojom_cpp_typemap build rule.'))
+  parser.add_argument('--output',
+                      type=str,
+                      required=True,
+                      help='The path to which to write the generated JSON.')
+  params, typemap_params = parser.parse_known_args()
+  typemaps = ParseTypemapArgs(typemap_params)
+  if params.cpp_config_path:
+    typemaps.update(LoadCppTypemapConfig(params.cpp_config_path))
+  missing = [path for path in params.dependency if not os.path.exists(path)]
+  if missing:
+    raise IOError('Missing dependencies: %s' % ', '.join(missing))
+  for path in params.dependency:
+    typemaps.update(ReadTypemap(path))
+
+  WriteFile(json.dumps({'c++': typemaps}, indent=2), params.output)
+
+
+if __name__ == '__main__':
+  main()
diff --git a/utils/ipc/mojo/public/tools/bindings/mojom.gni b/utils/ipc/mojo/public/tools/bindings/mojom.gni
new file mode 100644
index 00000000..a739fa6e
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/mojom.gni
@@ -0,0 +1,1941 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/jumbo.gni")
+import("//third_party/closure_compiler/closure_args.gni")
+import("//third_party/closure_compiler/compile_js.gni")
+import("//third_party/protobuf/proto_library.gni")
+import("//ui/webui/webui_features.gni")
+
+# TODO(rockot): Maybe we can factor these dependencies out of //mojo. They're
+# used to conditionally enable message ID scrambling in a way which is
+# consistent across toolchains and which is affected by branded vs non-branded
+# Chrome builds. Ideally we could create some generic knobs here that could be
+# flipped elsewhere though.
+import("//build/config/chrome_build.gni")
+import("//build/config/chromecast_build.gni")
+import("//build/config/chromeos/ui_mode.gni")
+import("//build/config/nacl/config.gni")
+import("//build/toolchain/kythe.gni")
+import("//components/nacl/features.gni")
+import("//third_party/jinja2/jinja2.gni")
+import("//tools/ipc_fuzzer/ipc_fuzzer.gni")
+declare_args() {
+  # Indicates whether typemapping should be supported in this build
+  # configuration. This may be disabled when building external projects which
+  # depend on //mojo but which do not need/want all of the Chromium tree
+  # dependencies that come with typemapping.
+  #
+  # Note that (perhaps obviously) a huge amount of Chromium code will not build
+  # with typemapping disabled, so it is never valid to set this to |false| in
+  # any Chromium build configuration.
+  enable_mojom_typemapping = true
+
+  # Controls message ID scrambling behavior. If |true|, message IDs are
+  # scrambled (i.e. randomized based on the contents of //chrome/VERSION) on
+  # non-Chrome OS desktop platforms. Set to |false| to disable message ID
+  # scrambling on all platforms.
+  enable_mojom_message_id_scrambling = true
+
+  # Enables Closure compilation of generated JS lite bindings. In environments
+  # where compilation is supported, any mojom target "foo" will also have a
+  # corresponding "foo_js_library_for_compile" target generated.
+  enable_mojom_closure_compile = enable_js_type_check && optimize_webui
+
+  # Enables generating Typescript bindings and compiling them to JS bindings.
+  enable_typescript_bindings = false
+
+  # Enables generating javascript fuzzing-related code and the bindings for the
+  # MojoLPM fuzzer targets. Off by default.
+  enable_mojom_fuzzer = false
+}
+
+# NOTE: We would like to avoid scrambling message IDs where it doesn't add
+# value, so we limit the behavior to desktop builds for now. There is some
+# redundancy in the conditions here, but it is tolerated for clarity:
+# We're explicit about Mac, Windows, and Linux desktop support, but it's
+# also necessary to ensure that bindings in alternate toolchains (e.g.
+# NaCl IRT) are always consistent with the default toolchain; for that
+# reason we always enable scrambling within NaCl toolchains when possible,
+# as well as within the default toolchain when NaCl is enabled.
+#
+# Finally, because we *cannot* enable scrambling on Chrome OS (it would break
+# ARC) we have to explicitly opt out there even when NaCl is enabled (and
+# consequently also when building for NaCl toolchains.) For this reason we
+# check |target_os| explicitly, as it's consistent across all toolchains.
+enable_scrambled_message_ids =
+    enable_mojom_message_id_scrambling &&
+    (is_mac || is_win || (is_linux && !is_chromeos && !is_chromecast &&
+                          !chromeos_is_browser_only) ||
+     ((enable_nacl || is_nacl || is_nacl_nonsfi) &&
+      (target_os != "chromeos" && !chromeos_is_browser_only)))
+
+_mojom_tools_root = "//mojo/public/tools"
+_mojom_library_root = "$_mojom_tools_root/mojom/mojom"
+mojom_parser_script = "$_mojom_tools_root/mojom/mojom_parser.py"
+mojom_parser_sources = [
+  "$_mojom_library_root/__init__.py",
+  "$_mojom_library_root/error.py",
+  "$_mojom_library_root/generate/__init__.py",
+  "$_mojom_library_root/generate/constant_resolver.py",
+  "$_mojom_library_root/generate/generator.py",
+  "$_mojom_library_root/generate/module.py",
+  "$_mojom_library_root/generate/pack.py",
+  "$_mojom_library_root/generate/template_expander.py",
+  "$_mojom_library_root/generate/translate.py",
+  "$_mojom_library_root/parse/__init__.py",
+  "$_mojom_library_root/parse/ast.py",
+  "$_mojom_library_root/parse/lexer.py",
+  "$_mojom_library_root/parse/parser.py",
+]
+
+mojom_generator_root = "$_mojom_tools_root/bindings"
+mojom_generator_script = "$mojom_generator_root/mojom_bindings_generator.py"
+mojom_generator_sources =
+    mojom_parser_sources + [
+      "$mojom_generator_root/generators/mojom_cpp_generator.py",
+      "$mojom_generator_root/generators/mojom_java_generator.py",
+      "$mojom_generator_root/generators/mojom_mojolpm_generator.py",
+      "$mojom_generator_root/generators/mojom_js_generator.py",
+      "$mojom_generator_root/generators/mojom_ts_generator.py",
+      "$mojom_generator_script",
+    ]
+
+if (enable_scrambled_message_ids) {
+  declare_args() {
+    # The path to a file whose contents can be used as the basis for a message
+    # ID scrambling salt.
+    mojom_message_id_salt_path = "//chrome/VERSION"
+
+    # The path to a file whose contents will be concatenated to the contents of
+    # the file at |mojom_message_id_salt_path| to form a complete salt for
+    # message ID scrambling. May be the empty string, in which case the contents
+    # of the above file alone are used as the complete salt.
+    if (is_chrome_branded) {
+      mojom_message_id_salt_suffix_path =
+          "//mojo/internal/chrome-message-id-salt-suffix"
+    } else {
+      mojom_message_id_salt_suffix_path = ""
+    }
+  }
+
+  assert(mojom_message_id_salt_path != "")
+  message_scrambling_args = [
+    "--scrambled_message_id_salt_path",
+    rebase_path(mojom_message_id_salt_path, root_build_dir),
+  ]
+  message_scrambling_inputs = [ mojom_message_id_salt_path ]
+
+  if (mojom_message_id_salt_suffix_path != "") {
+    message_scrambling_args += [
+      "--scrambled_message_id_salt_path",
+      rebase_path(mojom_message_id_salt_suffix_path, root_build_dir),
+    ]
+    message_scrambling_inputs += [ mojom_message_id_salt_suffix_path ]
+  }
+} else {
+  message_scrambling_args = []
+  message_scrambling_inputs = []
+}
+
+if (enable_mojom_typemapping) {
+  _bindings_configuration_files =
+      [ "//mojo/public/tools/bindings/chromium_bindings_configuration.gni" ]
+  _bindings_configurations = []
+  foreach(config_file, _bindings_configuration_files) {
+    _bindings_configurations += [ read_file(config_file, "scope") ]
+  }
+  foreach(configuration, _bindings_configurations) {
+    # Check that the mojom field of each typemap refers to a mojom that exists.
+    foreach(typemap, configuration.typemaps) {
+      _typemap_config = {
+      }
+      _typemap_config = typemap.config
+      read_file(_typemap_config.mojom, "")
+    }
+  }
+} else {
+  _bindings_configuration_files = []
+  _bindings_configurations = [
+    {
+      typemaps = []
+      component_macro_suffix = ""
+    },
+  ]
+}
+
+if (!is_ios) {
+  _bindings_configurations += [
+    {
+      variant = "blink"
+      component_macro_suffix = "_BLINK"
+      for_blink = true
+      typemaps = []
+    },
+  ]
+}
+
+# Generates targets for building C++, JavaScript and Java bindings from mojom
+# files. The output files will go under the generated file directory tree with
+# the same path as each input file.
+#
+# Other targets should depend on one of these generated targets (where "foo"
+# is the target name):
+#
+#   foo
+#       C++ bindings.
+#
+#   foo_blink
+#       C++ bindings using Blink standard types.
+#
+#   foo_java
+#       Java bindings.
+#
+#   foo_js
+#       JavaScript bindings; used as compile-time dependency.
+#
+#   foo_js_data_deps
+#       JavaScript bindings; used as run-time dependency.
+#
+# Parameters:
+#
+#   sources (optional if one of the deps sets listed below is present)
+#       List of source .mojom files to compile.
+#
+#   deps (optional)
+#       Note: this can contain only other mojom targets.
+#
+#       DEPRECATED: This is synonymous with public_deps because all mojom
+#       dependencies must be public by design. Please use public_deps.
+#
+#   public_deps (optional)
+#       Note: this can contain only other mojom targets.
+#
+#   parser_deps (optional)
+#       List of non-mojom targets required for the mojom sources to be parsed.
+#
+#   import_dirs (optional)
+#       List of import directories that will get added when processing sources.
+#
+#   testonly (optional)
+#
+#   visibility (optional)
+#
+#   visibility_blink (optional)
+#       The value to use for visibility for the blink variant. If unset,
+#       |visibility| is used.
+#
+#   cpp_only (optional)
+#       If set to true, only the C++ bindings targets will be generated.
+#
+#       NOTE: If the global |enable_mojom_fuzzer| build arg is true, JS bindings
+#       will still be generated even when |cpp_only| is set to |true|, unless
+#       you also set |enable_fuzzing| to |false| in your mojom target.
+#
+#   cpp_typemaps (optional)
+#       A list of typemaps to be applied to the generated C++ bindings for this
+#       mojom target. Note that this only applies to the non-Blink variant of
+#       generated C++ bindings.
+#
+#       Every typemap is a GN scope describing how one or more mojom types maps
+#       to a non-mojom C++ type, including necessary deps and headers required
+#       for the mapping to work. See the Typemaps section below.
+#
+#   blink_cpp_typemaps (optional)
+#       Same as above, but for the Blink variant of generated C++ bindings.
+#
+#   generate_java (optional)
+#       If set to true, Java bindings are generated for Android builds. If
+#       |cpp_only| is set to true, it overrides this to prevent generation of
+#       Java bindings.
+#
+#   enable_fuzzing (optional)
+#       Enables generation of fuzzing sources for the target if the global build
+#       arg |enable_mojom_fuzzer| is also set to |true|. Defaults to |true|. If
+#       fuzzing generation is enabled for a target, the target will always
+#       generate JS bindings even if |cpp_only| is set to |true|. See note
+#       above.
+#
+#   support_lazy_serialization (optional)
+#       If set to |true|, generated C++ bindings will effectively prefer to
+#       transmit messages in an unserialized form when going between endpoints
+#       in the same process. This avoids the runtime cost of serialization,
+#       deserialization, and validation logic at the expensive of increased
+#       code size. Defaults to |false|.
+#
+#   disable_variants (optional)
+#       If |true|, no variant sources will be generated for the target. Defaults
+#       to |false|.
+#
+#   disallow_native_types (optional)
+#       If set to |true|, mojoms in this target may not apply the [Native]
+#       attribute to struct or enum declarations. This avoids emitting code
+#       which depends on legacy IPC serialization. Default is |false|, meaning
+#       [Native] types are allowed.
+#
+#   disallow_interfaces (optional)
+#       If set to |true|, mojoms in this target may not define interfaces.
+#       Generates bindings with a smaller set of dependencies. Defaults to
+#       |false|.
+#
+#   scramble_message_ids (optional)
+#       If set to |true| (the default), generated mojom interfaces will use
+#       scrambled ordinal identifiers in encoded messages.
+#
+#   component_output_prefix (optional)
+#       The prefix to use for the output_name of any component library emitted
+#       for generated C++ bindings. If this is omitted, C++ bindings targets are
+#       emitted as source_sets instead. Because this controls the name of the
+#       output shared library binary in the root output directory, it must be
+#       unique across the entire build configuration.
+#
+#       This is required if |component_macro_prefix| is specified.
+#
+#   component_macro_prefix (optional)
+#       This specifies a macro prefix to use for component export macros and
+#       should therefore be globally unique in the project. For example if this
+#       is "FOO_BAR", then the generated C++ sources will be built with
+#       IS_FOO_BAR_{suffix}_IMPL defined, and the generated public headers will
+#       annotate public symbol definitions with
+#       COMPONENT_EXPORT(FOO_BAR_{suffix}). "suffix" in this case depends on
+#       which internal subtarget is generating the code (e.g. "SHARED", or a
+#       variant name like "BLINK").
+#
+#   enabled_features (optional)
+#       Definitions in a mojom file can be guarded by an EnableIf attribute. If
+#       the value specified by the attribute does not match any items in the
+#       list of enabled_features, the definition will be disabled, with no code
+#       emitted for it.
+#
+#   generate_closure_exports (optional)
+#       Generates JS lite bindings will use goog.provide and goog.require
+#       annotations to export its symbols and import core Mojo bindings support
+#       and other mojom dependency modules. Use this if you plan to compile your
+#       bindings into a larger JS binary. Defaults to |false|, instead
+#       generating JS lite bindings which assume they will be manually loaded in
+#       correct dependency order. Note that this only has an effect if
+#       the |enable_mojom_closure_compile| global arg is set to |true| as well.
+#
+#   use_typescript_sources (optional)
+#       Uses the Typescript generator to generate JavaScript bindings.
+#
+#   js_generate_struct_deserializers (optional)
+#       Generates JS deerialize methods for structs.
+#
+#   extra_cpp_template_paths (optional)
+#       List of extra C++ templates that are used to generate additional source
+#       and/or header files. The templates should end with extension ".tmpl".
+#
+# The following parameters are used to support the component build. They are
+# needed so that bindings which are linked with a component can use the same
+# export settings for classes. The first three are for the chromium variant, and
+# the last three are for the blink variant. These parameters can also override
+# |component_macro_prefix| for a specific variant, allowing e.g. one variant
+# to be linked into a larger non-mojom component target, while all other
+# variants get their own unique component target.
+#   export_class_attribute (optional)
+#       The attribute to add to the class declaration. e.g. "CONTENT_EXPORT"
+#   export_define (optional)
+#       A define to be added to the source_set which is needed by the export
+#       header. e.g. "CONTENT_IMPLEMENTATION=1"
+#   export_header (optional)
+#       A header to be added to the generated bindings to support the component
+#       build. e.g. "content/common/content_export.h"
+#   export_class_attribute_blink (optional)
+#   export_define_blink (optional)
+#   export_header_blink (optional)
+#       These three parameters are the blink variants of the previous 3.
+#
+# The following parameters are used to correct component build dependencies.
+# They are needed so mojom-mojom dependencies follow the rule that dependencies
+# on a source set in another component are replaced by a dependency on the
+# containing component. The first two are for the chromium variant; the other
+# two are for the blink variant.
+#   overridden_deps (optional)
+#       The list of mojom deps to be overridden.
+#   component_deps (optional)
+#       The list of component deps to add to replace overridden_deps.
+#   overridden_deps_blink (optional)
+#   component_deps_blink (optional)
+#       These two parameters are the blink variants of the previous two.
+#
+#   check_includes_blink (optional)
+#       Overrides the check_includes variable for the blink variant.
+#       If check_includes_blink is not defined, the check_includes variable
+#       retains its original value.
+#
+# Typemaps
+# ========
+# The cpp_typemaps and blink_cpp_typemaps each specify an optional list of
+# typemapping configurations. Each configuration is a GN scope with metadata
+# describing what and how to map.
+#
+# Typemap scope parameters:
+#   types
+#       A list of type specifications for this typemap. Each type specification
+#       is a nested GN scope which can be expressed with the following syntax:
+#
+#           {
+#             mojom = "foo.mojom.Bar"
+#             cpp = "::foo::LegitBar"
+#             move_only = true
+#             # etc...
+#           }
+#
+#       Each type specification supports the following values:
+#
+#         mojom (required)
+#             The fully qualified name of a mojom type to be mapped. This is a
+#             string like "foo.mojom.Bar".
+#
+#         cpp (required)
+#             The fully qualified name of the C++ type to which the mojom type
+#             should be mapped in generated bindings. This is a string like
+#             "::base::Value" or "std::vector<::base::Value>".
+#
+#         move_only (optional)
+#             A boolean value (default false) which indicates whether the C++
+#             type is move-only. If true, generated bindings will pass the type
+#             by value and use std::move() at call sites.
+#
+#         copyable_pass_by_value (optional)
+#             A boolean value (default false) which effectively indicates
+#             whether the C++ type is very cheap to copy. If so, generated
+#             bindings will pass by value but not use std::move() at call sites.
+#
+#         nullable_is_same_type (optional)
+#             A boolean value (default false) which indicates that the C++ type
+#             has some baked-in semantic notion of a "null" state. If true, the
+#             traits for the type must define IsNull and SetToNull methods.
+#
+#             When false, nullable fields are represented by wrapping the C++
+#             type with base::Optional, and null values are simply
+#             base::nullopt.
+#
+#         hashable (optional)
+#             A boolean value (default false) indicating whether the C++ type is
+#             hashable. Set to true if true AND needed (i.e. you need to use the
+#             type as the key of a mojom map).
+#
+#         force_serialize (optional)
+#             A boolean value (default false) which disables lazy serialization
+#             of the typemapped type if lazy serialization is enabled for the
+#             mojom target applying this typemap.
+#
+# Additional typemap scope parameters:
+#
+#   traits_headers (optional)
+#       Headers which must be included in the generated mojom in order for
+#       serialization to be possible. This generally means including at least
+#       the header for the corresponding mojom traits definitions.
+#
+#   traits_private_headers (optional)
+#       Headers which must be included in generated C++ serialization code for
+#       a mojom using the typemap. This should be used only when including a
+#       header in |traits_headers| is problematic for compilation, as is
+#       sometimes the case with legacy IPC message headers.
+#
+#   traits_sources (optional)
+#       The references to the source files (typically a single .cc and .h file)
+#       defining an appropriate set of EnumTraits or StructTraits, etc for the
+#       the type-mapping. Using this will cause the listed sources to be
+#       integrated directly into the dependent mojom's generated type-mapping
+#       targets.
+#
+#       Prefer using |traits_public_deps| over inlined |traits_sources|, as this
+#       will generally lead to easier build maintenance over time.
+#
+#       NOTE: If a typemap is shared by Blink and non-Blink bindings, you cannot
+#       use this and MUST use |traits_public_deps| to reference traits built
+#       within a separate target.
+#
+#   traits_deps / traits_public_deps (optional)
+#       Any dependencies of sources in |traits_headers| or |traits_sources| must
+#       be listed here.
+#
+template("mojom") {
+  assert(
+      defined(invoker.sources) || defined(invoker.deps) ||
+          defined(invoker.public_deps),
+      "\"sources\" or \"deps\" must be defined for the $target_name template.")
+
+  if (defined(invoker.export_class_attribute) ||
+      defined(invoker.export_define) || defined(invoker.export_header)) {
+    assert(defined(invoker.export_class_attribute))
+    assert(defined(invoker.export_define))
+    assert(defined(invoker.export_header))
+  }
+  if (defined(invoker.export_class_attribute_blink) ||
+      defined(invoker.export_define_blink) ||
+      defined(invoker.export_header_blink)) {
+    assert(defined(invoker.export_class_attribute_blink))
+    assert(defined(invoker.export_define_blink))
+    assert(defined(invoker.export_header_blink))
+
+    # Not all platforms use the Blink variant, so make sure GN doesn't complain
+    # about these values being inconsequential.
+    not_needed(invoker,
+               [
+                 "export_class_attribute_blink",
+                 "export_define_blink",
+                 "export_header_blink",
+               ])
+  }
+  if (defined(invoker.overridden_deps) || defined(invoker.component_deps)) {
+    assert(defined(invoker.overridden_deps))
+    assert(defined(invoker.component_deps))
+  }
+
+  if (defined(invoker.overridden_deps_blink) ||
+      defined(invoker.component_deps_blink)) {
+    assert(defined(invoker.overridden_deps_blink))
+    assert(defined(invoker.component_deps_blink))
+  }
+
+  # Type-mapping may be disabled or we may not generate C++ bindings.
+  not_needed(invoker,
+             [
+               "cpp_typemaps",
+               "blink_cpp_typemaps",
+             ])
+
+  require_full_cpp_deps =
+      !defined(invoker.disallow_native_types) ||
+      !invoker.disallow_native_types || !defined(invoker.disallow_interfaces) ||
+      !invoker.disallow_interfaces
+
+  all_deps = []
+  if (defined(invoker.deps)) {
+    all_deps += invoker.deps
+  }
+  if (defined(invoker.public_deps)) {
+    all_deps += invoker.public_deps
+  }
+
+  if (defined(invoker.component_macro_prefix)) {
+    assert(defined(invoker.component_output_prefix))
+  }
+
+  group("${target_name}__is_mojom") {
+  }
+
+  # Explicitly ensure that all dependencies (invoker.deps and
+  # invoker.public_deps) are mojom targets.
+  group("${target_name}__check_deps_are_all_mojom") {
+    deps = []
+    foreach(d, all_deps) {
+      name = get_label_info(d, "label_no_toolchain")
+      toolchain = get_label_info(d, "toolchain")
+      deps += [ "${name}__is_mojom(${toolchain})" ]
+    }
+  }
+
+  sources_list = []
+  if (defined(invoker.sources)) {
+    sources_list = invoker.sources
+  }
+
+  # Reset sources_assignment_filter for the BUILD.gn file to prevent
+  # regression during the migration of Chromium away from the feature.
+  # See docs/no_sources_assignment_filter.md for more information.
+  # TODO(crbug.com/1018739): remove this when migration is done.
+  set_sources_assignment_filter([])
+
+  # Listed sources may be relative to the current target dir, or they may be
+  # absolute paths, including paths to generated mojom files. While those are
+  # fine as-is for input references, deriving output paths can be more subtle.
+  #
+  # Here we rewrite all source paths to be relative to the root build dir and
+  # strip any root_gen_dir prefixes.
+  #
+  # So for a target in //foo/bar with:
+  #
+  #     sources = [
+  #       "a.mojom",
+  #       "b/c.mojom",
+  #       "//baz/d.mojom",
+  #       "$target_gen_dir/e.mojom",
+  #     ]
+  #
+  # output_file_base_paths will be:
+  #
+  #     [
+  #       "foo/bar/a.mojom",
+  #       "foo/bar/b/c.mojom",
+  #       "baz/d.mojom",
+  #       "foo/bar/e.mojom",
+  #     ]
+  #
+  # This result is essentially a list of base filename paths which are suitable
+  # for the naming of any generated output files derived from their
+  # corresponding input mojoms. These paths are always considered to be relative
+  # to root_gen_dir.
+  source_abspaths = rebase_path(sources_list, "//")
+  output_file_base_paths = []
+  foreach(path, source_abspaths) {
+    output_file_base_paths +=
+        [ string_replace(path, rebase_path(root_gen_dir, "//") + "/", "") ]
+  }
+
+  # Sanity check that either all input files have a .mojom extension, or
+  # all input files have a .test-mojom extension AND |testonly| is |true|.
+  sources_list_filenames =
+      process_file_template(sources_list, "{{source_file_part}}")
+  sources_list_filenames_with_mojom_extension =
+      process_file_template(sources_list, "{{source_name_part}}.mojom")
+  if (sources_list_filenames != sources_list_filenames_with_mojom_extension) {
+    sources_list_filenames_with_test_mojom_extension =
+        process_file_template(sources_list, "{{source_name_part}}.test-mojom")
+    if (sources_list_filenames ==
+        sources_list_filenames_with_test_mojom_extension) {
+      assert(
+          defined(invoker.testonly) && invoker.testonly,
+          "mojom targets for .test-mojom files must set |testonly| to |true|")
+    } else {
+      assert(
+          false,
+          "One or more mojom files has an invalid extension. The only " +
+              "allowed extensions are .mojom and .test-mojom, and any given " +
+              "mojom target must use one or the other exclusively.")
+    }
+  }
+
+  build_metadata_filename = "$target_gen_dir/$target_name.build_metadata"
+  build_metadata = {
+  }
+  build_metadata.sources = rebase_path(sources_list)
+  build_metadata.deps = []
+  foreach(dep, all_deps) {
+    dep_target_gen_dir = get_label_info(dep, "target_gen_dir")
+    dep_name = get_label_info(dep, "name")
+    build_metadata.deps +=
+        [ rebase_path("$dep_target_gen_dir/$dep_name.build_metadata") ]
+  }
+  write_file(build_metadata_filename, build_metadata, "json")
+
+  generate_fuzzing =
+      (!defined(invoker.enable_fuzzing) || invoker.enable_fuzzing) &&
+      enable_mojom_fuzzer && (!defined(invoker.testonly) || !invoker.testonly)
+
+  parser_target_name = "${target_name}__parser"
+  parser_deps = []
+  foreach(dep, all_deps) {
+    _label = get_label_info(dep, "label_no_toolchain")
+    parser_deps += [ "${_label}__parser" ]
+  }
+  if (defined(invoker.parser_deps)) {
+    parser_deps += invoker.parser_deps
+  }
+  if (sources_list == []) {
+    # Even without sources we generate a parser target to at least forward
+    # other parser dependencies.
+    group(parser_target_name) {
+      public_deps = parser_deps
+    }
+  } else {
+    enabled_features = []
+    if (defined(invoker.enabled_features)) {
+      enabled_features += invoker.enabled_features
+    }
+    if (is_posix) {
+      enabled_features += [ "is_posix" ]
+    }
+    if (is_android) {
+      enabled_features += [ "is_android" ]
+    } else if (is_chromeos) {
+      enabled_features += [ "is_chromeos" ]
+    } else if (is_fuchsia) {
+      enabled_features += [ "is_fuchsia" ]
+    } else if (is_ios) {
+      enabled_features += [ "is_ios" ]
+    } else if (is_linux) {
+      enabled_features += [ "is_linux" ]
+    } else if (is_mac) {
+      enabled_features += [ "is_mac" ]
+    } else if (is_win) {
+      enabled_features += [ "is_win" ]
+    }
+
+    action(parser_target_name) {
+      script = mojom_parser_script
+      inputs = mojom_parser_sources + [ build_metadata_filename ]
+      sources = sources_list
+      deps = parser_deps
+      outputs = []
+      foreach(base_path, output_file_base_paths) {
+        filename = get_path_info(base_path, "file")
+        dirname = get_path_info(base_path, "dir")
+        outputs += [ "$root_gen_dir/$dirname/${filename}-module" ]
+      }
+
+      filelist = []
+      foreach(source, sources_list) {
+        filelist += [ rebase_path(source) ]
+      }
+      response_file_contents = filelist
+
+      args = [
+        # Resolve relative input mojom paths against both the root src dir and
+        # the root gen dir.
+        "--input-root",
+        rebase_path("//"),
+        "--input-root",
+        rebase_path(root_gen_dir),
+
+        "--output-root",
+        rebase_path(root_gen_dir),
+
+        "--mojom-file-list={{response_file_name}}",
+
+        "--check-imports",
+        rebase_path(build_metadata_filename),
+      ]
+
+      foreach(enabled_feature, enabled_features) {
+        args += [
+          "--enable-feature",
+          enabled_feature,
+        ]
+      }
+    }
+  }
+
+  generator_cpp_message_ids_target_name = "${target_name}__generate_message_ids"
+
+  # Generate code that is shared by different variants.
+  if (sources_list != []) {
+    common_generator_args = [
+      "--use_bundled_pylibs",
+      "-o",
+      rebase_path(root_gen_dir, root_build_dir),
+      "generate",
+      "-d",
+      rebase_path("//", root_build_dir),
+      "-I",
+      rebase_path("//", root_build_dir),
+      "--bytecode_path",
+      rebase_path("$root_gen_dir/mojo/public/tools/bindings", root_build_dir),
+    ]
+
+    if (defined(invoker.disallow_native_types) &&
+        invoker.disallow_native_types) {
+      common_generator_args += [ "--disallow_native_types" ]
+    }
+
+    if (defined(invoker.disallow_interfaces) && invoker.disallow_interfaces) {
+      common_generator_args += [ "--disallow_interfaces" ]
+    }
+
+    if (defined(invoker.import_dirs)) {
+      foreach(import_dir, invoker.import_dirs) {
+        common_generator_args += [
+          "-I",
+          rebase_path(import_dir, root_build_dir),
+        ]
+      }
+    }
+
+    if (defined(invoker.component_macro_prefix)) {
+      shared_component_export_macro =
+          "COMPONENT_EXPORT(${invoker.component_macro_prefix}_SHARED)"
+      shared_component_impl_macro =
+          "IS_${invoker.component_macro_prefix}_SHARED_IMPL"
+      shared_component_output_name = "${invoker.component_output_prefix}_shared"
+    } else if (defined(invoker.export_class_attribute_shared) ||
+               defined(invoker.export_class_attribute)) {
+      if (defined(invoker.export_class_attribute_shared)) {
+        assert(defined(invoker.export_header_shared))
+        shared_component_export_macro = invoker.export_class_attribute_shared
+        shared_component_impl_macro = invoker.export_define_shared
+      } else {
+        assert(!defined(invoker.export_header_shared))
+
+        # If no explicit shared attribute/define was provided by the invoker,
+        # we derive some reasonable settings frorm the default variant.
+        shared_component_export_macro = "COMPONENT_EXPORT(MOJOM_SHARED_" +
+                                        invoker.export_class_attribute + ")"
+        shared_component_impl_macro =
+            "IS_MOJOM_SHARED_" + invoker.export_class_attribute + "_IMPL"
+      }
+
+      if (defined(invoker.component_output_prefix)) {
+        shared_component_output_name =
+            "${invoker.component_output_prefix}_shared"
+      } else {
+        shared_component_output_name = "${target_name}_shared"
+      }
+    }
+
+    action(generator_cpp_message_ids_target_name) {
+      script = mojom_generator_script
+      inputs = mojom_generator_sources + jinja2_sources
+      sources = sources_list
+      deps = [
+        ":$parser_target_name",
+        "//mojo/public/tools/bindings:precompile_templates",
+      ]
+      if (defined(invoker.parser_deps)) {
+        deps += invoker.parser_deps
+      }
+      outputs = []
+      args = common_generator_args
+      filelist = []
+      foreach(source, sources_list) {
+        filelist += [ rebase_path("$source", root_build_dir) ]
+      }
+      foreach(base_path, output_file_base_paths) {
+        outputs += [ "$root_gen_dir/$base_path-shared-message-ids.h" ]
+      }
+
+      response_file_contents = filelist
+
+      args += [
+        "--filelist={{response_file_name}}",
+        "--generate_non_variant_code",
+        "--generate_message_ids",
+        "-g",
+        "c++",
+      ]
+
+      if (!defined(invoker.scramble_message_ids) ||
+          invoker.scramble_message_ids) {
+        inputs += message_scrambling_inputs
+        args += message_scrambling_args
+      }
+    }
+
+    generator_shared_target_name = "${target_name}_shared__generator"
+    action(generator_shared_target_name) {
+      visibility = [ ":*" ]
+      script = mojom_generator_script
+      inputs = mojom_generator_sources + jinja2_sources
+      sources = sources_list
+      deps = [
+        ":$parser_target_name",
+        "//mojo/public/tools/bindings:precompile_templates",
+      ]
+      if (defined(invoker.parser_deps)) {
+        deps += invoker.parser_deps
+      }
+
+      outputs = []
+      args = common_generator_args
+      filelist = []
+      foreach(source, sources_list) {
+        filelist += [ rebase_path("$source", root_build_dir) ]
+      }
+      foreach(base_path, output_file_base_paths) {
+        outputs += [
+          "$root_gen_dir/$base_path-params-data.h",
+          "$root_gen_dir/$base_path-shared-internal.h",
+          "$root_gen_dir/$base_path-shared.cc",
+          "$root_gen_dir/$base_path-shared.h",
+        ]
+      }
+
+      response_file_contents = filelist
+
+      args += [
+        "--filelist={{response_file_name}}",
+        "--generate_non_variant_code",
+        "-g",
+        "c++",
+      ]
+
+      if (defined(shared_component_export_macro)) {
+        args += [
+          "--export_attribute",
+          shared_component_export_macro,
+          "--export_header",
+          "base/component_export.h",
+        ]
+      }
+
+      # Enable adding annotations to generated C++ headers that are used for
+      # cross-references in CodeSearch.
+      if (enable_kythe_annotations) {
+        args += [ "--enable_kythe_annotations" ]
+      }
+    }
+  } else {
+    group(generator_cpp_message_ids_target_name) {
+    }
+  }
+
+  shared_cpp_sources_target_name = "${target_name}_shared_cpp_sources"
+  jumbo_source_set(shared_cpp_sources_target_name) {
+    if (defined(invoker.testonly)) {
+      testonly = invoker.testonly
+    }
+    deps = []
+    public_deps = []
+    if (output_file_base_paths != []) {
+      sources = []
+      foreach(base_path, output_file_base_paths) {
+        sources += [
+          "$root_gen_dir/$base_path-params-data.h",
+          "$root_gen_dir/$base_path-shared-internal.h",
+          "$root_gen_dir/$base_path-shared.cc",
+          "$root_gen_dir/$base_path-shared.h",
+        ]
+      }
+      public_deps += [ ":$generator_shared_target_name" ]
+    }
+    if (require_full_cpp_deps) {
+      public_deps += [ "//mojo/public/cpp/bindings" ]
+    } else {
+      public_deps += [ "//mojo/public/cpp/bindings:bindings_base" ]
+    }
+    foreach(d, all_deps) {
+      # Resolve the name, so that a target //mojo/something becomes
+      # //mojo/something:something and we can append shared_cpp_sources_suffix
+      # to get the cpp dependency name.
+      full_name = get_label_info("$d", "label_no_toolchain")
+      public_deps += [ "${full_name}_shared" ]
+    }
+    if (defined(shared_component_impl_macro)) {
+      defines = [ shared_component_impl_macro ]
+    }
+  }
+
+  shared_cpp_library_target_name = "${target_name}_shared"
+  if (defined(shared_component_output_name)) {
+    component(shared_cpp_library_target_name) {
+      if (defined(invoker.testonly)) {
+        testonly = invoker.testonly
+      }
+      output_name = "$shared_component_output_name"
+      public_deps = [ ":$shared_cpp_sources_target_name" ]
+    }
+  } else {
+    group(shared_cpp_library_target_name) {
+      if (defined(invoker.testonly)) {
+        testonly = invoker.testonly
+      }
+      public_deps = [ ":$shared_cpp_sources_target_name" ]
+    }
+  }
+
+  if (generate_fuzzing) {
+    # This block generates the proto files used for the MojoLPM fuzzer,
+    # and the corresponding proto targets that will be linked in the fuzzer
+    # targets. These are independent of the typemappings, and can be done
+    # separately here.
+
+    generator_mojolpm_proto_target_name =
+        "${target_name}_mojolpm_proto_generator"
+    action(generator_mojolpm_proto_target_name) {
+      script = mojom_generator_script
+      inputs = mojom_generator_sources + jinja2_sources
+      sources = invoker.sources
+      deps = [
+        ":$parser_target_name",
+        "//mojo/public/tools/bindings:precompile_templates",
+      ]
+
+      outputs = []
+      args = common_generator_args
+      filelist = []
+      foreach(source, invoker.sources) {
+        filelist += [ rebase_path("$source", root_build_dir) ]
+        outputs += [ "$target_gen_dir/$source.mojolpm.proto" ]
+      }
+
+      response_file_contents = filelist
+
+      args += [
+        "--filelist={{response_file_name}}",
+        "--generate_non_variant_code",
+        "-g",
+        "mojolpm",
+      ]
+    }
+
+    mojolpm_proto_target_name = "${target_name}_mojolpm_proto"
+    if (defined(invoker.sources)) {
+      proto_library(mojolpm_proto_target_name) {
+        testonly = true
+        generate_python = false
+        sources = process_file_template(
+                invoker.sources,
+                [ "{{source_gen_dir}}/{{source_file_part}}.mojolpm.proto" ])
+        import_dirs = [ "${root_gen_dir}" ]
+        proto_in_dir = "${root_gen_dir}"
+        proto_out_dir = "."
+        proto_deps = [ "//mojo/public/tools/fuzzers:mojolpm_proto_copy" ]
+        proto_deps += [ ":$generator_mojolpm_proto_target_name" ]
+        link_deps = [ "//mojo/public/tools/fuzzers:mojolpm_proto" ]
+
+        foreach(d, all_deps) {
+          # Resolve the name, so that a target //mojo/something becomes
+          # //mojo/something:something and we can append mojolpm_proto_suffix
+          # to get the proto dependency name.
+          full_name = get_label_info("$d", "label_no_toolchain")
+          proto_deps += [ "${full_name}_mojolpm_proto" ]
+          link_deps += [ "${full_name}_mojolpm_proto" ]
+        }
+      }
+    } else {
+      group(mojolpm_proto_target_name) {
+        testonly = true
+        public_deps = [ "//mojo/public/tools/fuzzers:mojolpm_proto" ]
+        if (defined(generator_shared_target_name)) {
+          public_deps += [ ":$generator_shared_target_name" ]
+        }
+        foreach(d, all_deps) {
+          # Resolve the name, so that a target //mojo/something becomes
+          # //mojo/something:something and we can append #mojolpm_proto_suffix
+          # to get the proto dependency name.
+          full_name = get_label_info("$d", "label_no_toolchain")
+          public_deps += [ "${full_name}_mojolpm_proto" ]
+        }
+      }
+    }
+  }
+
+  # Generate code for variants.
+  if (!defined(invoker.disable_variants) || !invoker.disable_variants) {
+    enabled_configurations = _bindings_configurations
+  } else {
+    first_config = _bindings_configurations[0]
+    assert(!defined(first_config.variant))
+    enabled_configurations = [ first_config ]
+  }
+  foreach(bindings_configuration, enabled_configurations) {
+    cpp_only = false
+    if (defined(invoker.cpp_only)) {
+      cpp_only = invoker.cpp_only
+    }
+    variant_suffix = ""
+    if (defined(bindings_configuration.variant)) {
+      variant = bindings_configuration.variant
+      variant_suffix = "_${variant}"
+      cpp_only = true
+    }
+
+    cpp_typemap_configs = []
+    export_defines = []
+    export_defines_overridden = false
+    force_source_set = false
+    if (defined(bindings_configuration.for_blink) &&
+        bindings_configuration.for_blink) {
+      if (defined(invoker.blink_cpp_typemaps)) {
+        cpp_typemap_configs = invoker.blink_cpp_typemaps
+      }
+      if (defined(invoker.export_define_blink)) {
+        export_defines_overridden = true
+        export_defines = [ invoker.export_define_blink ]
+        force_source_set = true
+      }
+    } else {
+      if (defined(invoker.cpp_typemaps)) {
+        cpp_typemap_configs = invoker.cpp_typemaps
+      }
+
+      if (defined(invoker.export_define)) {
+        export_defines_overridden = true
+        export_defines = [ invoker.export_define ]
+        force_source_set = true
+      }
+    }
+    not_needed([ "cpp_typemap_configs" ])
+
+    if (!export_defines_overridden && defined(invoker.component_macro_prefix)) {
+      output_name_override =
+          "${invoker.component_output_prefix}${variant_suffix}"
+      export_defines =
+          [ "IS_${invoker.component_macro_prefix}" +
+            "${bindings_configuration.component_macro_suffix}_IMPL" ]
+    }
+
+    export_args = []
+    export_args_overridden = false
+    if (defined(bindings_configuration.for_blink) &&
+        bindings_configuration.for_blink) {
+      if (defined(invoker.export_class_attribute_blink)) {
+        export_args_overridden = true
+        export_args += [
+          "--export_attribute",
+          invoker.export_class_attribute_blink,
+          "--export_header",
+          invoker.export_header_blink,
+        ]
+      }
+    } else if (defined(invoker.export_class_attribute)) {
+      export_args_overridden = true
+      export_args += [
+        "--export_attribute",
+        invoker.export_class_attribute,
+        "--export_header",
+        invoker.export_header,
+      ]
+    }
+
+    if (!export_args_overridden && defined(invoker.component_macro_prefix)) {
+      export_args += [
+        "--export_attribute",
+        "COMPONENT_EXPORT(${invoker.component_macro_prefix}" +
+            "${bindings_configuration.component_macro_suffix})",
+        "--export_header",
+        "base/component_export.h",
+      ]
+    }
+
+    generate_java = false
+    if (!cpp_only && defined(invoker.generate_java)) {
+      generate_java = invoker.generate_java
+    }
+    type_mappings_target_name = "${target_name}${variant_suffix}__type_mappings"
+    type_mappings_path =
+        "$target_gen_dir/${target_name}${variant_suffix}__type_mappings"
+    active_typemaps = []
+    if (sources_list != []) {
+      generator_cpp_output_suffixes = []
+      variant_dash_suffix = ""
+      if (defined(variant)) {
+        variant_dash_suffix = "-${variant}"
+      }
+      generator_cpp_output_suffixes += [
+        "${variant_dash_suffix}-forward.h",
+        "${variant_dash_suffix}-import-headers.h",
+        "${variant_dash_suffix}-test-utils.cc",
+        "${variant_dash_suffix}-test-utils.h",
+        "${variant_dash_suffix}.cc",
+        "${variant_dash_suffix}.h",
+      ]
+      foreach(source, sources_list) {
+        # TODO(sammc): Use a map instead of a linear scan when GN supports maps.
+        foreach(typemap, bindings_configuration.typemaps) {
+          _typemap_config = {
+          }
+          _typemap_config = typemap.config
+          if (get_path_info(source, "abspath") == _typemap_config.mojom) {
+            active_typemaps += [ typemap ]
+          }
+        }
+      }
+
+      generator_target_name = "${target_name}${variant_suffix}__generator"
+      action(generator_target_name) {
+        visibility = [ ":*" ]
+        script = mojom_generator_script
+        inputs = mojom_generator_sources + jinja2_sources
+        sources = sources_list
+        deps = [
+          ":$parser_target_name",
+          ":$type_mappings_target_name",
+          "//mojo/public/tools/bindings:precompile_templates",
+        ]
+        if (defined(invoker.parser_deps)) {
+          deps += invoker.parser_deps
+        }
+        outputs = []
+        args = common_generator_args + export_args
+        filelist = []
+        foreach(source, sources_list) {
+          filelist += [ rebase_path("$source", root_build_dir) ]
+        }
+        foreach(base_path, output_file_base_paths) {
+          outputs += [
+            "$root_gen_dir/${base_path}${variant_dash_suffix}-forward.h",
+            "$root_gen_dir/${base_path}${variant_dash_suffix}-import-headers.h",
+            "$root_gen_dir/${base_path}${variant_dash_suffix}-test-utils.cc",
+            "$root_gen_dir/${base_path}${variant_dash_suffix}-test-utils.h",
+            "$root_gen_dir/${base_path}${variant_dash_suffix}.cc",
+            "$root_gen_dir/${base_path}${variant_dash_suffix}.h",
+          ]
+          if (generate_fuzzing && !defined(bindings_configuration.variant)) {
+            outputs += [
+              "$root_gen_dir/${base_path}${variant_dash_suffix}-mojolpm.cc",
+              "$root_gen_dir/${base_path}${variant_dash_suffix}-mojolpm.h",
+            ]
+          }
+        }
+
+        response_file_contents = filelist
+
+        args += [
+          "--filelist={{response_file_name}}",
+          "-g",
+        ]
+
+        if (generate_fuzzing && !defined(bindings_configuration.variant)) {
+          args += [ "c++,mojolpm" ]
+        } else {
+          args += [ "c++" ]
+        }
+
+        if (defined(bindings_configuration.variant)) {
+          args += [
+            "--variant",
+            bindings_configuration.variant,
+          ]
+        }
+
+        args += [
+          "--typemap",
+          rebase_path(type_mappings_path, root_build_dir),
+        ]
+
+        if (defined(bindings_configuration.for_blink) &&
+            bindings_configuration.for_blink) {
+          args += [ "--for_blink" ]
+        }
+
+        if (defined(invoker.support_lazy_serialization) &&
+            invoker.support_lazy_serialization) {
+          args += [ "--support_lazy_serialization" ]
+        }
+
+        if (enable_kythe_annotations) {
+          args += [ "--enable_kythe_annotations" ]
+        }
+
+        if (!defined(invoker.scramble_message_ids) ||
+            invoker.scramble_message_ids) {
+          inputs += message_scrambling_inputs
+          args += message_scrambling_args
+        }
+
+        if (defined(invoker.extra_cpp_template_paths)) {
+          foreach(extra_cpp_template, invoker.extra_cpp_template_paths) {
+            args += [
+              "--extra_cpp_template_paths",
+              rebase_path(extra_cpp_template, root_build_dir),
+            ]
+            assert(
+                get_path_info(extra_cpp_template, "extension") == "tmpl",
+                "--extra_cpp_template_paths only accepts template files ending in extension .tmpl")
+            foreach(base_path, output_file_base_paths) {
+              template_file_name = get_path_info("$extra_cpp_template", "name")
+              outputs += [ "$root_gen_dir/${base_path}${variant_dash_suffix}-${template_file_name}" ]
+            }
+          }
+        }
+      }
+    }
+
+    if (generate_fuzzing && !defined(variant)) {
+      # This block contains the C++ targets for the MojoLPM fuzzer, we need to
+      # do this here so that we can use the typemap configuration for the
+      # empty-variant Mojo target.
+
+      mojolpm_target_name = "${target_name}_mojolpm"
+      mojolpm_generator_target_name = "${target_name}__generator"
+      source_set(mojolpm_target_name) {
+        # There are still a few missing header dependencies between mojo targets
+        # with typemaps and the dependencies of their typemap headers. It would
+        # be good to enable include checking for these in the future though.
+        check_includes = false
+        testonly = true
+        if (defined(invoker.sources)) {
+          sources = process_file_template(
+                  invoker.sources,
+                  [
+                    "{{source_gen_dir}}/{{source_file_part}}-mojolpm.cc",
+                    "{{source_gen_dir}}/{{source_file_part}}-mojolpm.h",
+                  ])
+          deps = []
+        } else {
+          sources = []
+          deps = []
+        }
+
+        public_deps = [
+          ":$generator_shared_target_name",
+
+          # NB: hardcoded dependency on the no-variant variant generator, since
+          # mojolpm only uses the no-variant type.
+          ":$mojolpm_generator_target_name",
+          ":$mojolpm_proto_target_name",
+          "//mojo/public/tools/fuzzers:mojolpm",
+        ]
+
+        foreach(d, all_deps) {
+          # Resolve the name, so that a target //mojo/something becomes
+          # //mojo/something:something and we can append variant_suffix to
+          # get the cpp dependency name.
+          full_name = get_label_info("$d", "label_no_toolchain")
+          public_deps += [ "${full_name}_mojolpm" ]
+        }
+
+        foreach(typemap, active_typemaps) {
+          _typemap_config = {
+          }
+          _typemap_config = typemap.config
+
+          if (defined(_typemap_config.deps)) {
+            deps += _typemap_config.deps
+          }
+          if (defined(_typemap_config.public_deps)) {
+            public_deps += _typemap_config.public_deps
+          }
+        }
+        foreach(config, cpp_typemap_configs) {
+          if (defined(config.traits_deps)) {
+            deps += config.traits_deps
+          }
+          if (defined(config.traits_public_deps)) {
+            public_deps += config.traits_public_deps
+          }
+        }
+      }
+    }
+
+    # Write the typemapping configuration for this target out to a file to be
+    # validated by a Python script. This helps catch mistakes that can't
+    # be caught by logic in GN.
+    _typemap_config_filename =
+        "$target_gen_dir/${target_name}${variant_suffix}.typemap_config"
+    _typemap_stamp_filename = "${_typemap_config_filename}.validated"
+    _typemap_validator_target_name = "${type_mappings_target_name}__validator"
+    _rebased_typemap_configs = []
+    foreach(config, cpp_typemap_configs) {
+      _rebased_config = {
+      }
+      _rebased_config = config
+      if (defined(config.traits_headers)) {
+        _rebased_config.traits_headers = []
+        _rebased_config.traits_headers =
+            rebase_path(config.traits_headers, "//")
+      }
+      if (defined(config.traits_private_headers)) {
+        _rebased_config.traits_private_headers = []
+        _rebased_config.traits_private_headers =
+            rebase_path(config.traits_private_headers, "//")
+      }
+      _rebased_typemap_configs += [ _rebased_config ]
+    }
+    write_file(_typemap_config_filename, _rebased_typemap_configs, "json")
+    _mojom_target_name = target_name
+    action(_typemap_validator_target_name) {
+      script = "$mojom_generator_root/validate_typemap_config.py"
+      inputs = [ _typemap_config_filename ]
+      outputs = [ _typemap_stamp_filename ]
+      args = [
+        get_label_info(_mojom_target_name, "label_no_toolchain"),
+        rebase_path(_typemap_config_filename),
+        rebase_path(_typemap_stamp_filename),
+      ]
+    }
+
+    action(type_mappings_target_name) {
+      inputs = _bindings_configuration_files + mojom_generator_sources +
+               jinja2_sources + [ _typemap_stamp_filename ]
+      outputs = [ type_mappings_path ]
+      script = "$mojom_generator_root/generate_type_mappings.py"
+      deps = [ ":$_typemap_validator_target_name" ]
+      args = [
+        "--output",
+        rebase_path(type_mappings_path, root_build_dir),
+      ]
+
+      foreach(d, all_deps) {
+        name = get_label_info(d, "label_no_toolchain")
+        toolchain = get_label_info(d, "toolchain")
+        dependency_output = "${name}${variant_suffix}__type_mappings"
+        dependency_target = "${dependency_output}(${toolchain})"
+        deps += [ dependency_target ]
+        dependency_output_dir =
+            get_label_info(dependency_output, "target_gen_dir")
+        dependency_name = get_label_info(dependency_output, "name")
+        dependency_path =
+            rebase_path("$dependency_output_dir/${dependency_name}",
+                        root_build_dir)
+        args += [
+          "--dependency",
+          dependency_path,
+        ]
+      }
+
+      if (sources_list != []) {
+        # TODO(sammc): Pass the typemap description in a file to avoid command
+        # line length limitations.
+        typemap_description = []
+        foreach(typemap, active_typemaps) {
+          _typemap_config = {
+          }
+          _typemap_config = typemap.config
+
+          typemap_description += [ "--start-typemap" ]
+          if (defined(_typemap_config.public_headers)) {
+            foreach(value, _typemap_config.public_headers) {
+              typemap_description += [ "public_headers=$value" ]
+            }
+          }
+          if (defined(_typemap_config.traits_headers)) {
+            foreach(value, _typemap_config.traits_headers) {
+              typemap_description += [ "traits_headers=$value" ]
+            }
+          }
+          foreach(value, _typemap_config.type_mappings) {
+            typemap_description += [ "type_mappings=$value" ]
+          }
+
+          # The typemap configuration files are not actually used as inputs here
+          # but this establishes a necessary build dependency to ensure that
+          # typemap changes force a rebuild of affected targets.
+          if (defined(typemap.filename)) {
+            inputs += [ typemap.filename ]
+          }
+        }
+        args += typemap_description
+
+        # Newer GN-based typemaps are aggregated into a single config.
+        inputs += [ _typemap_config_filename ]
+        args += [
+          "--cpp-typemap-config",
+          rebase_path(_typemap_config_filename, root_build_dir),
+        ]
+      }
+    }
+
+    group("${target_name}${variant_suffix}_headers") {
+      public_deps = []
+      if (sources_list != []) {
+        public_deps += [
+          ":$generator_cpp_message_ids_target_name",
+          ":$generator_shared_target_name",
+          ":$generator_target_name",
+        ]
+      }
+      foreach(d, all_deps) {
+        full_name = get_label_info("$d", "label_no_toolchain")
+        public_deps += [ "${full_name}${variant_suffix}_headers" ]
+      }
+    }
+
+    if (!force_source_set && defined(invoker.component_macro_prefix)) {
+      output_target_type = "component"
+    } else {
+      output_target_type = "source_set"
+    }
+
+    js_data_deps_target_name = target_name + "_js_data_deps"
+    not_needed([ "js_data_deps_target_name" ])
+
+    target("jumbo_" + output_target_type, "${target_name}${variant_suffix}") {
+      if (defined(output_name_override)) {
+        output_name = output_name_override
+      }
+      if (defined(bindings_configuration.for_blink) &&
+          bindings_configuration.for_blink &&
+          defined(invoker.visibility_blink)) {
+        visibility = invoker.visibility_blink
+      } else if (defined(invoker.visibility)) {
+        visibility = invoker.visibility
+      }
+      if (defined(invoker.testonly)) {
+        testonly = invoker.testonly
+      }
+      defines = export_defines
+      if (output_file_base_paths != []) {
+        sources = []
+        foreach(base_path, output_file_base_paths) {
+          foreach(suffix, generator_cpp_output_suffixes) {
+            sources += [ "$root_gen_dir/${base_path}$suffix" ]
+          }
+        }
+      }
+      deps = [
+        ":$generator_cpp_message_ids_target_name",
+        "//mojo/public/cpp/bindings:struct_traits",
+        "//mojo/public/interfaces/bindings:bindings_headers",
+      ]
+      public_deps = [
+        ":$shared_cpp_library_target_name",
+        "//base",
+      ]
+      if (require_full_cpp_deps) {
+        public_deps += [ "//mojo/public/cpp/bindings" ]
+      } else {
+        public_deps += [ "//mojo/public/cpp/bindings:bindings_base" ]
+      }
+
+      if (sources_list != []) {
+        public_deps += [ ":$generator_target_name" ]
+      }
+      foreach(d, all_deps) {
+        # Resolve the name, so that a target //mojo/something becomes
+        # //mojo/something:something and we can append variant_suffix to
+        # get the cpp dependency name.
+        full_name = get_label_info("$d", "label_no_toolchain")
+        public_deps += [ "${full_name}${variant_suffix}" ]
+      }
+      if (defined(bindings_configuration.for_blink) &&
+          bindings_configuration.for_blink) {
+        if (defined(invoker.overridden_deps_blink)) {
+          foreach(d, invoker.overridden_deps_blink) {
+            # Resolve the name, so that a target //mojo/something becomes
+            # //mojo/something:something and we can append variant_suffix
+            # to get the cpp dependency name.
+            full_name = get_label_info("$d", "label_no_toolchain")
+            public_deps -= [ "${full_name}${variant_suffix}" ]
+          }
+          public_deps += invoker.component_deps_blink
+        }
+        if (defined(invoker.check_includes_blink)) {
+          check_includes = invoker.check_includes_blink
+        }
+      } else {
+        if (defined(invoker.check_includes_blink)) {
+          not_needed(invoker, [ "check_includes_blink" ])
+        }
+        if (defined(invoker.overridden_deps)) {
+          foreach(d, invoker.overridden_deps) {
+            # Resolve the name, so that a target //mojo/something becomes
+            # //mojo/something:something and we can append variant_suffix
+            # to get the cpp dependency name.
+            full_name = get_label_info("$d", "label_no_toolchain")
+            public_deps -= [ "${full_name}${variant_suffix}" ]
+          }
+          public_deps += invoker.component_deps
+        }
+      }
+      foreach(typemap, active_typemaps) {
+        _typemap_config = {
+        }
+        _typemap_config = typemap.config
+        if (defined(_typemap_config.sources)) {
+          sources += _typemap_config.sources
+        }
+        if (defined(_typemap_config.public_deps)) {
+          public_deps += _typemap_config.public_deps
+        }
+        if (defined(_typemap_config.deps)) {
+          deps += _typemap_config.deps
+        }
+      }
+      foreach(config, cpp_typemap_configs) {
+        if (defined(config.traits_sources)) {
+          sources += config.traits_sources
+        }
+        if (defined(config.traits_deps)) {
+          deps += config.traits_deps
+        }
+        if (defined(config.traits_public_deps)) {
+          public_deps += config.traits_public_deps
+        }
+      }
+      if (defined(invoker.export_header)) {
+        sources += [ "//" + invoker.export_header ]
+      }
+      if (defined(bindings_configuration.for_blink) &&
+          bindings_configuration.for_blink) {
+        public_deps += [ "//mojo/public/cpp/bindings:wtf_support" ]
+      }
+
+      if (generate_fuzzing) {
+        # Generate JS bindings by default if IPC fuzzer is enabled.
+        public_deps += [ ":$js_data_deps_target_name" ]
+      }
+    }
+
+    if (generate_java && is_android) {
+      import("//build/config/android/rules.gni")
+
+      java_generator_target_name = target_name + "_java__generator"
+      if (sources_list != []) {
+        action(java_generator_target_name) {
+          script = mojom_generator_script
+          inputs = mojom_generator_sources + jinja2_sources
+          sources = sources_list
+          deps = [
+            ":$parser_target_name",
+            ":$type_mappings_target_name",
+            "//mojo/public/tools/bindings:precompile_templates",
+          ]
+          outputs = []
+          args = common_generator_args
+          filelist = []
+          foreach(source, sources_list) {
+            filelist += [ rebase_path("$source", root_build_dir) ]
+          }
+          foreach(base_path, output_file_base_paths) {
+            outputs += [ "$root_gen_dir/$base_path.srcjar" ]
+          }
+
+          response_file_contents = filelist
+
+          args += [
+            "--filelist={{response_file_name}}",
+            "-g",
+            "java",
+          ]
+
+          if (!defined(invoker.scramble_message_ids) ||
+              invoker.scramble_message_ids) {
+            inputs += message_scrambling_inputs
+            args += message_scrambling_args
+          }
+        }
+      } else {
+        group(java_generator_target_name) {
+        }
+      }
+
+      java_srcjar_target_name = target_name + "_java_sources"
+      action(java_srcjar_target_name) {
+        script = "//build/android/gyp/zip.py"
+        inputs = []
+        if (output_file_base_paths != []) {
+          foreach(base_path, output_file_base_paths) {
+            inputs += [ "$root_gen_dir/${base_path}.srcjar" ]
+          }
+        }
+        output = "$target_gen_dir/$target_name.srcjar"
+        outputs = [ output ]
+        rebase_inputs = rebase_path(inputs, root_build_dir)
+        rebase_output = rebase_path(output, root_build_dir)
+        args = [
+          "--input-zips=$rebase_inputs",
+          "--output=$rebase_output",
+        ]
+        deps = []
+        if (sources_list != []) {
+          deps = [ ":$java_generator_target_name" ]
+        }
+      }
+
+      java_target_name = target_name + "_java"
+      android_library(java_target_name) {
+        forward_variables_from(invoker, [ "enable_bytecode_checks" ])
+        deps = [
+          "//base:base_java",
+          "//mojo/public/java:bindings_java",
+          "//mojo/public/java:system_java",
+        ]
+
+        # Disable warnings/checks on these generated files.
+        chromium_code = false
+
+        foreach(d, all_deps) {
+          # Resolve the name, so that a target //mojo/something becomes
+          # //mojo/something:something and we can append "_java" to get the java
+          # dependency name.
+          full_name = get_label_info(d, "label_no_toolchain")
+          deps += [ "${full_name}_java" ]
+        }
+
+        srcjar_deps = [ ":$java_srcjar_target_name" ]
+      }
+    }
+  }
+
+  use_typescript_for_target =
+      enable_typescript_bindings && defined(invoker.use_typescript_sources) &&
+      invoker.use_typescript_sources
+
+  if (!use_typescript_for_target && defined(invoker.use_typescript_sources)) {
+    not_needed(invoker, [ "use_typescript_sources" ])
+  }
+
+  if ((generate_fuzzing || !defined(invoker.cpp_only) || !invoker.cpp_only) &&
+      !use_typescript_for_target) {
+    if (sources_list != []) {
+      generator_js_target_name = "${target_name}_js__generator"
+      action(generator_js_target_name) {
+        script = mojom_generator_script
+        inputs = mojom_generator_sources + jinja2_sources
+        sources = sources_list
+        deps = [
+          ":$parser_target_name",
+          "//mojo/public/tools/bindings:precompile_templates",
+        ]
+        if (defined(invoker.parser_deps)) {
+          deps += invoker.parser_deps
+        }
+        outputs = []
+        args = common_generator_args
+        filelist = []
+        foreach(source, sources_list) {
+          filelist += [ rebase_path("$source", root_build_dir) ]
+        }
+        foreach(base_path, output_file_base_paths) {
+          outputs += [
+            "$root_gen_dir/$base_path.js",
+            "$root_gen_dir/$base_path.externs.js",
+            "$root_gen_dir/$base_path-lite.js",
+            "$root_gen_dir/$base_path.html",
+            "$root_gen_dir/$base_path-lite-for-compile.js",
+          ]
+        }
+
+        response_file_contents = filelist
+
+        args += [
+          "--filelist={{response_file_name}}",
+          "-g",
+          "javascript",
+          "--js_bindings_mode=new",
+        ]
+
+        if (defined(invoker.js_generate_struct_deserializers) &&
+            invoker.js_generate_struct_deserializers) {
+          args += [ "--js_generate_struct_deserializers" ]
+        }
+
+        if (!defined(invoker.scramble_message_ids) ||
+            invoker.scramble_message_ids) {
+          inputs += message_scrambling_inputs
+          args += message_scrambling_args
+        }
+
+        if (generate_fuzzing) {
+          args += [ "--generate_fuzzing" ]
+        }
+      }
+    }
+
+    js_target_name = target_name + "_js"
+    group(js_target_name) {
+      public_deps = []
+      if (sources_list != []) {
+        public_deps += [ ":$generator_js_target_name" ]
+      }
+
+      foreach(d, all_deps) {
+        full_name = get_label_info(d, "label_no_toolchain")
+        public_deps += [ "${full_name}_js" ]
+      }
+    }
+
+    group(js_data_deps_target_name) {
+      deps = []
+      if (sources_list != []) {
+        data = []
+        foreach(base_path, output_file_base_paths) {
+          data += [
+            "$root_gen_dir/${base_path}.js",
+            "$root_gen_dir/${base_path}-lite.js",
+          ]
+        }
+        deps += [ ":$generator_js_target_name" ]
+      }
+
+      data_deps = []
+      foreach(d, all_deps) {
+        full_name = get_label_info(d, "label_no_toolchain")
+        data_deps += [ "${full_name}_js_data_deps" ]
+      }
+    }
+
+    js_library_target_name = "${target_name}_js_library"
+    if (sources_list != []) {
+      js_library(js_library_target_name) {
+        extra_public_deps = [ ":$generator_js_target_name" ]
+        sources = []
+        foreach(base_path, output_file_base_paths) {
+          sources += [ "$root_gen_dir/${base_path}-lite.js" ]
+        }
+        externs_list = [
+          "${externs_path}/mojo_core.js",
+          "${externs_path}/pending.js",
+        ]
+
+        deps = []
+        foreach(d, all_deps) {
+          full_name = get_label_info(d, "label_no_toolchain")
+          deps += [ "${full_name}_js_library" ]
+        }
+      }
+    } else {
+      group(js_library_target_name) {
+      }
+    }
+
+    js_library_for_compile_target_name = "${target_name}_js_library_for_compile"
+    if (sources_list != []) {
+      js_library(js_library_for_compile_target_name) {
+        extra_public_deps = [ ":$generator_js_target_name" ]
+        sources = []
+        foreach(base_path, output_file_base_paths) {
+          sources += [ "$root_gen_dir/${base_path}-lite-for-compile.js" ]
+        }
+        externs_list = [
+          "${externs_path}/mojo_core.js",
+          "${externs_path}/pending.js",
+        ]
+        deps = []
+        if (!defined(invoker.disallow_native_types)) {
+          deps += [ "//mojo/public/js:bindings_lite_sources" ]
+        }
+        foreach(d, all_deps) {
+          full_name = get_label_info(d, "label_no_toolchain")
+          deps += [ "${full_name}_js_library_for_compile" ]
+        }
+      }
+    } else {
+      group(js_library_for_compile_target_name) {
+      }
+    }
+  }
+  if ((generate_fuzzing || !defined(invoker.cpp_only) || !invoker.cpp_only) &&
+      use_typescript_for_target) {
+    generator_js_target_names = []
+    source_filelist = []
+    foreach(source, sources_list) {
+      source_filelist += [ rebase_path("$source", root_build_dir) ]
+    }
+
+    dependency_types = [
+      {
+        name = "regular"
+        ts_extension = ".ts"
+        js_extension = ".js"
+      },
+      {
+        name = "es_modules"
+        ts_extension = ".m.ts"
+        js_extension = ".m.js"
+      },
+    ]
+
+    foreach(dependency_type, dependency_types) {
+      ts_outputs = []
+      js_outputs = []
+
+      foreach(base_path, output_file_base_paths) {
+        ts_outputs +=
+            [ "$root_gen_dir/$base_path-lite${dependency_type.ts_extension}" ]
+        js_outputs +=
+            [ "$root_gen_dir/$base_path-lite${dependency_type.js_extension}" ]
+      }
+
+      # Generate Typescript bindings.
+      generator_ts_target_name =
+          "${target_name}_${dependency_type.name}__ts__generator"
+      action(generator_ts_target_name) {
+        script = mojom_generator_script
+        inputs = mojom_generator_sources + jinja2_sources
+        sources = sources_list
+        deps = [
+          ":$parser_target_name",
+          "//mojo/public/tools/bindings:precompile_templates",
+        ]
+
+        outputs = ts_outputs
+        args = common_generator_args
+        response_file_contents = source_filelist
+
+        args += [
+          "--filelist={{response_file_name}}",
+          "-g",
+          "typescript",
+        ]
+
+        if (dependency_type.name == "es_modules") {
+          args += [ "--ts_use_es_modules" ]
+        }
+
+        # TODO(crbug.com/1007587): Support scramble_message_ids.
+        # TODO(crbug.com/1007591): Support generate_fuzzing.
+      }
+
+      # Create tsconfig.json for the generated Typescript.
+      tsconfig_filename =
+          "$target_gen_dir/$target_name-${dependency_type.name}-tsconfig.json"
+      tsconfig = {
+      }
+      tsconfig.compilerOptions = {
+        composite = true
+        target = "es6"
+        module = "es6"
+        lib = [
+          "es6",
+          "esnext.bigint",
+        ]
+        strict = true
+      }
+      tsconfig.files = []
+      foreach(base_path, output_file_base_paths) {
+        tsconfig.files += [ rebase_path(
+                "$root_gen_dir/$base_path-lite${dependency_type.ts_extension}",
+                target_gen_dir,
+                root_gen_dir) ]
+      }
+      tsconfig.references = []
+
+      # Get tsconfigs for deps.
+      foreach(d, all_deps) {
+        dep_target_gen_dir = rebase_path(get_label_info(d, "target_gen_dir"))
+        dep_name = get_label_info(d, "name")
+        reference = {
+        }
+        reference.path = "$dep_target_gen_dir/$dep_name-${dependency_type.name}-tsconfig.json"
+        tsconfig.references += [ reference ]
+      }
+      write_file(tsconfig_filename, tsconfig, "json")
+
+      # Compile previously generated Typescript to Javascript.
+      generator_js_target_name =
+          "${target_name}_${dependency_type.name}__js__generator"
+      generator_js_target_names += [ generator_js_target_name ]
+
+      action(generator_js_target_name) {
+        script = "$mojom_generator_root/compile_typescript.py"
+        sources = ts_outputs
+        outputs = js_outputs
+        public_deps = [ ":$generator_ts_target_name" ]
+        foreach(d, all_deps) {
+          full_name = get_label_info(d, "label_no_toolchain")
+          public_deps +=
+              [ "${full_name}_${dependency_type.name}__js__generator" ]
+        }
+
+        absolute_tsconfig_path =
+            rebase_path(tsconfig_filename, "", target_gen_dir)
+        args = [ "--tsconfig_path=$absolute_tsconfig_path" ]
+      }
+    }
+
+    js_target_name = target_name + "_js"
+    group(js_target_name) {
+      public_deps = []
+      if (sources_list != []) {
+        foreach(generator_js_target_name, generator_js_target_names) {
+          public_deps += [ ":$generator_js_target_name" ]
+        }
+      }
+
+      foreach(d, all_deps) {
+        full_name = get_label_info(d, "label_no_toolchain")
+        public_deps += [ "${full_name}_js" ]
+      }
+    }
+
+    group(js_data_deps_target_name) {
+      data = js_outputs
+      deps = []
+      foreach(generator_js_target_name, generator_js_target_names) {
+        deps += [ ":$generator_js_target_name" ]
+      }
+      data_deps = []
+      foreach(d, all_deps) {
+        full_name = get_label_info(d, "label_no_toolchain")
+        data_deps += [ "${full_name}_js_data_deps" ]
+      }
+    }
+  }
+}
+
+# A helper for the mojom() template above when component libraries are desired
+# for generated C++ bindings units. Supports all the same arguments as mojom()
+# except for the optional |component_output_prefix| and |component_macro_prefix|
+# arguments. These are instead shortened to |output_prefix| and |macro_prefix|
+# and are *required*.
+template("mojom_component") {
+  assert(defined(invoker.output_prefix) && defined(invoker.macro_prefix))
+
+  mojom(target_name) {
+    forward_variables_from(invoker,
+                           "*",
+                           [
+                             "output_prefix",
+                             "macro_prefix",
+                           ])
+    component_output_prefix = invoker.output_prefix
+    component_macro_prefix = invoker.macro_prefix
+  }
+}
diff --git a/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator.py b/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator.py
new file mode 100755
index 00000000..da9efc71
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator.py
@@ -0,0 +1,390 @@
+#!/usr/bin/env python
+# Copyright 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""The frontend for the Mojo bindings system."""
+
+from __future__ import print_function
+
+import argparse
+
+import hashlib
+import importlib
+import json
+import os
+import pprint
+import re
+import struct
+import sys
+
+# Disable lint check for finding modules:
+# pylint: disable=F0401
+
+def _GetDirAbove(dirname):
+  """Returns the directory "above" this file containing |dirname| (which must
+  also be "above" this file)."""
+  path = os.path.abspath(__file__)
+  while True:
+    path, tail = os.path.split(path)
+    assert tail
+    if tail == dirname:
+      return path
+
+
+sys.path.insert(
+    0,
+    os.path.join(
+        os.path.dirname(os.path.dirname(os.path.abspath(__file__))), "mojom"))
+
+from mojom.error import Error
+import mojom.fileutil as fileutil
+from mojom.generate.module import Module
+from mojom.generate import template_expander
+from mojom.generate import translate
+from mojom.generate.generator import WriteFile
+
+sys.path.append(
+    os.path.join(_GetDirAbove("mojo"), "tools", "diagnosis"))
+import crbug_1001171
+
+
+_BUILTIN_GENERATORS = {
+    "c++": "mojom_cpp_generator",
+    "javascript": "mojom_js_generator",
+    "java": "mojom_java_generator",
+    "mojolpm": "mojom_mojolpm_generator",
+    "typescript": "mojom_ts_generator",
+}
+
+
+def LoadGenerators(generators_string):
+  if not generators_string:
+    return []  # No generators.
+
+  generators = {}
+  for generator_name in [s.strip() for s in generators_string.split(",")]:
+    language = generator_name.lower()
+    if language not in _BUILTIN_GENERATORS:
+      print("Unknown generator name %s" % generator_name)
+      sys.exit(1)
+    generator_module = importlib.import_module(
+        "generators.%s" % _BUILTIN_GENERATORS[language])
+    generators[language] = generator_module
+  return generators
+
+
+def MakeImportStackMessage(imported_filename_stack):
+  """Make a (human-readable) message listing a chain of imports. (Returned
+  string begins with a newline (if nonempty) and does not end with one.)"""
+  return ''.join(
+      reversed(["\n  %s was imported by %s" % (a, b) for (a, b) in \
+                    zip(imported_filename_stack[1:], imported_filename_stack)]))
+
+
+class RelativePath(object):
+  """Represents a path relative to the source tree or generated output dir."""
+
+  def __init__(self, path, source_root, output_dir):
+    self.path = path
+    if path.startswith(source_root):
+      self.root = source_root
+    elif path.startswith(output_dir):
+      self.root = output_dir
+    else:
+      raise Exception("Invalid input path %s" % path)
+
+  def relative_path(self):
+    return os.path.relpath(
+        os.path.abspath(self.path), os.path.abspath(self.root))
+
+
+def _GetModulePath(path, output_dir):
+  return os.path.join(output_dir, path.relative_path() + '-module')
+
+
+def ScrambleMethodOrdinals(interfaces, salt):
+  already_generated = set()
+  for interface in interfaces:
+    i = 0
+    already_generated.clear()
+    for method in interface.methods:
+      if method.explicit_ordinal is not None:
+        continue
+      while True:
+        i = i + 1
+        if i == 1000000:
+          raise Exception("Could not generate %d method ordinals for %s" %
+              (len(interface.methods), interface.mojom_name))
+        # Generate a scrambled method.ordinal value. The algorithm doesn't have
+        # to be very strong, cryptographically. It just needs to be non-trivial
+        # to guess the results without the secret salt, in order to make it
+        # harder for a compromised process to send fake Mojo messages.
+        sha256 = hashlib.sha256(salt)
+        sha256.update(interface.mojom_name.encode('utf-8'))
+        sha256.update(str(i).encode('utf-8'))
+        # Take the first 4 bytes as a little-endian uint32.
+        ordinal = struct.unpack('<L', sha256.digest()[:4])[0]
+        # Trim to 31 bits, so it always fits into a Java (signed) int.
+        ordinal = ordinal & 0x7fffffff
+        if ordinal in already_generated:
+          continue
+        already_generated.add(ordinal)
+        method.ordinal = ordinal
+        method.ordinal_comment = (
+            'The %s value is based on sha256(salt + "%s%d").' %
+            (ordinal, interface.mojom_name, i))
+        break
+
+
+def ReadFileContents(filename):
+  with open(filename, 'rb') as f:
+    return f.read()
+
+
+class MojomProcessor(object):
+  """Takes parsed mojom modules and generates language bindings from them.
+
+  Attributes:
+    _processed_files: {Dict[str, mojom.generate.module.Module]} Mapping from
+        relative mojom filename paths to the module AST for that mojom file.
+  """
+  def __init__(self, should_generate):
+    self._should_generate = should_generate
+    self._processed_files = {}
+    self._typemap = {}
+
+  def LoadTypemaps(self, typemaps):
+    # Support some very simple single-line comments in typemap JSON.
+    comment_expr = r"^\s*//.*$"
+    def no_comments(line):
+      return not re.match(comment_expr, line)
+    for filename in typemaps:
+      with open(filename) as f:
+        typemaps = json.loads("".join(filter(no_comments, f.readlines())))
+        for language, typemap in typemaps.items():
+          language_map = self._typemap.get(language, {})
+          language_map.update(typemap)
+          self._typemap[language] = language_map
+    if 'c++' in self._typemap:
+      self._typemap['mojolpm'] = self._typemap['c++']
+
+  def _GenerateModule(self, args, remaining_args, generator_modules,
+                      rel_filename, imported_filename_stack):
+    # Return the already-generated module.
+    if rel_filename.path in self._processed_files:
+      return self._processed_files[rel_filename.path]
+
+    if rel_filename.path in imported_filename_stack:
+      print("%s: Error: Circular dependency" % rel_filename.path + \
+          MakeImportStackMessage(imported_filename_stack + [rel_filename.path]))
+      sys.exit(1)
+
+    module_path = _GetModulePath(rel_filename, args.output_dir)
+    with open(module_path, 'rb') as f:
+      module = Module.Load(f)
+
+    if args.scrambled_message_id_salt_paths:
+      salt = b''.join(
+          map(ReadFileContents, args.scrambled_message_id_salt_paths))
+      ScrambleMethodOrdinals(module.interfaces, salt)
+
+    if self._should_generate(rel_filename.path):
+      for language, generator_module in generator_modules.items():
+        generator = generator_module.Generator(
+            module, args.output_dir, typemap=self._typemap.get(language, {}),
+            variant=args.variant, bytecode_path=args.bytecode_path,
+            for_blink=args.for_blink,
+            js_bindings_mode=args.js_bindings_mode,
+            js_generate_struct_deserializers=\
+                    args.js_generate_struct_deserializers,
+            export_attribute=args.export_attribute,
+            export_header=args.export_header,
+            generate_non_variant_code=args.generate_non_variant_code,
+            support_lazy_serialization=args.support_lazy_serialization,
+            disallow_native_types=args.disallow_native_types,
+            disallow_interfaces=args.disallow_interfaces,
+            generate_message_ids=args.generate_message_ids,
+            generate_fuzzing=args.generate_fuzzing,
+            enable_kythe_annotations=args.enable_kythe_annotations,
+            extra_cpp_template_paths=args.extra_cpp_template_paths,
+            generate_extra_cpp_only=args.generate_extra_cpp_only)
+        filtered_args = []
+        if hasattr(generator_module, 'GENERATOR_PREFIX'):
+          prefix = '--' + generator_module.GENERATOR_PREFIX + '_'
+          filtered_args = [arg for arg in remaining_args
+                           if arg.startswith(prefix)]
+        generator.GenerateFiles(filtered_args)
+
+    # Save result.
+    self._processed_files[rel_filename.path] = module
+    return module
+
+
+def _Generate(args, remaining_args):
+  if args.variant == "none":
+    args.variant = None
+
+  for idx, import_dir in enumerate(args.import_directories):
+    tokens = import_dir.split(":")
+    if len(tokens) >= 2:
+      args.import_directories[idx] = RelativePath(tokens[0], tokens[1],
+                                                  args.output_dir)
+    else:
+      args.import_directories[idx] = RelativePath(tokens[0], args.depth,
+                                                  args.output_dir)
+  generator_modules = LoadGenerators(args.generators_string)
+
+  fileutil.EnsureDirectoryExists(args.output_dir)
+
+  processor = MojomProcessor(lambda filename: filename in args.filename)
+  processor.LoadTypemaps(set(args.typemaps))
+
+  if args.filelist:
+    with open(args.filelist) as f:
+      args.filename.extend(f.read().split())
+
+  for filename in args.filename:
+    processor._GenerateModule(
+        args, remaining_args, generator_modules,
+        RelativePath(filename, args.depth, args.output_dir), [])
+
+  return 0
+
+
+def _Precompile(args, _):
+  generator_modules = LoadGenerators(",".join(_BUILTIN_GENERATORS.keys()))
+
+  template_expander.PrecompileTemplates(generator_modules, args.output_dir)
+  return 0
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Generate bindings from mojom files.")
+  parser.add_argument("--use_bundled_pylibs", action="store_true",
+                      help="use Python modules bundled in the SDK")
+  parser.add_argument(
+      "-o",
+      "--output_dir",
+      dest="output_dir",
+      default=".",
+      help="output directory for generated files")
+
+  subparsers = parser.add_subparsers()
+
+  generate_parser = subparsers.add_parser(
+      "generate", description="Generate bindings from mojom files.")
+  generate_parser.add_argument("filename", nargs="*",
+                               help="mojom input file")
+  generate_parser.add_argument("--filelist", help="mojom input file list")
+  generate_parser.add_argument("-d", "--depth", dest="depth", default=".",
+                               help="depth from source root")
+  generate_parser.add_argument("-g",
+                               "--generators",
+                               dest="generators_string",
+                               metavar="GENERATORS",
+                               default="c++,javascript,java,mojolpm",
+                               help="comma-separated list of generators")
+  generate_parser.add_argument(
+      "--gen_dir", dest="gen_directories", action="append", metavar="directory",
+      default=[], help="add a directory to be searched for the syntax trees.")
+  generate_parser.add_argument(
+      "-I", dest="import_directories", action="append", metavar="directory",
+      default=[],
+      help="add a directory to be searched for import files. The depth from "
+           "source root can be specified for each import by appending it after "
+           "a colon")
+  generate_parser.add_argument("--typemap", action="append", metavar="TYPEMAP",
+                               default=[], dest="typemaps",
+                               help="apply TYPEMAP to generated output")
+  generate_parser.add_argument("--variant", dest="variant", default=None,
+                               help="output a named variant of the bindings")
+  generate_parser.add_argument(
+      "--bytecode_path", required=True, help=(
+          "the path from which to load template bytecode; to generate template "
+          "bytecode, run %s precompile BYTECODE_PATH" % os.path.basename(
+              sys.argv[0])))
+  generate_parser.add_argument("--for_blink", action="store_true",
+                               help="Use WTF types as generated types for mojo "
+                               "string/array/map.")
+  generate_parser.add_argument(
+      "--js_bindings_mode", choices=["new", "old"], default="old",
+      help="This option only affects the JavaScript bindings. The value could "
+      "be \"new\" to generate new-style lite JS bindings in addition to the "
+      "old, or \"old\" to only generate old bindings.")
+  generate_parser.add_argument(
+      "--js_generate_struct_deserializers", action="store_true",
+      help="Generate javascript deserialize methods for structs in "
+      "mojom-lite.js file")
+  generate_parser.add_argument(
+      "--export_attribute", default="",
+      help="Optional attribute to specify on class declaration to export it "
+      "for the component build.")
+  generate_parser.add_argument(
+      "--export_header", default="",
+      help="Optional header to include in the generated headers to support the "
+      "component build.")
+  generate_parser.add_argument(
+      "--generate_non_variant_code", action="store_true",
+      help="Generate code that is shared by different variants.")
+  generate_parser.add_argument(
+      "--scrambled_message_id_salt_path",
+      dest="scrambled_message_id_salt_paths",
+      help="If non-empty, the path to a file whose contents should be used as"
+      "a salt for generating scrambled message IDs. If this switch is specified"
+      "more than once, the contents of all salt files are concatenated to form"
+      "the salt value.", default=[], action="append")
+  generate_parser.add_argument(
+      "--support_lazy_serialization",
+      help="If set, generated bindings will serialize lazily when possible.",
+      action="store_true")
+  generate_parser.add_argument(
+      "--extra_cpp_template_paths",
+      dest="extra_cpp_template_paths",
+      action="append",
+      metavar="path_to_template",
+      default=[],
+      help="Provide a path to a new template (.tmpl) that is used to generate "
+      "additional C++ source/header files ")
+  generate_parser.add_argument(
+      "--generate_extra_cpp_only",
+      help="If set and extra_cpp_template_paths provided, will only generate"
+      "extra_cpp_template related C++ bindings",
+      action="store_true")
+  generate_parser.add_argument(
+      "--disallow_native_types",
+      help="Disallows the [Native] attribute to be specified on structs or "
+      "enums within the mojom file.", action="store_true")
+  generate_parser.add_argument(
+      "--disallow_interfaces",
+      help="Disallows interface definitions within the mojom file. It is an "
+      "error to specify this flag when processing a mojom file which defines "
+      "any interface.", action="store_true")
+  generate_parser.add_argument(
+      "--generate_message_ids",
+      help="Generates only the message IDs header for C++ bindings. Note that "
+      "this flag only matters if --generate_non_variant_code is also "
+      "specified.", action="store_true")
+  generate_parser.add_argument(
+      "--generate_fuzzing",
+      action="store_true",
+      help="Generates additional bindings for fuzzing in JS.")
+  generate_parser.add_argument(
+      "--enable_kythe_annotations",
+      action="store_true",
+      help="Adds annotations for kythe metadata generation.")
+
+  generate_parser.set_defaults(func=_Generate)
+
+  precompile_parser = subparsers.add_parser("precompile",
+      description="Precompile templates for the mojom bindings generator.")
+  precompile_parser.set_defaults(func=_Precompile)
+
+  args, remaining_args = parser.parse_known_args()
+  return args.func(args, remaining_args)
+
+
+if __name__ == "__main__":
+  with crbug_1001171.DumpStateOnLookupError():
+    sys.exit(main())
diff --git a/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator_unittest.py b/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator_unittest.py
new file mode 100644
index 00000000..bddbe3f4
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/mojom_bindings_generator_unittest.py
@@ -0,0 +1,62 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import unittest
+
+from mojom_bindings_generator import MakeImportStackMessage
+from mojom_bindings_generator import ScrambleMethodOrdinals
+
+
+class FakeIface(object):
+  def __init__(self):
+    self.mojom_name = None
+    self.methods = None
+
+
+class FakeMethod(object):
+  def __init__(self, explicit_ordinal=None):
+    self.explicit_ordinal = explicit_ordinal
+    self.ordinal = explicit_ordinal
+    self.ordinal_comment = None
+
+
+class MojoBindingsGeneratorTest(unittest.TestCase):
+  """Tests mojo_bindings_generator."""
+
+  def testMakeImportStackMessage(self):
+    """Tests MakeImportStackMessage()."""
+    self.assertEqual(MakeImportStackMessage(["x"]), "")
+    self.assertEqual(MakeImportStackMessage(["x", "y"]),
+                     "\n  y was imported by x")
+    self.assertEqual(MakeImportStackMessage(["x", "y", "z"]),
+                     "\n  z was imported by y\n  y was imported by x")
+
+  def testScrambleMethodOrdinals(self):
+    """Tests ScrambleMethodOrdinals()."""
+    interface = FakeIface()
+    interface.mojom_name = 'RendererConfiguration'
+    interface.methods = [
+        FakeMethod(),
+        FakeMethod(),
+        FakeMethod(),
+        FakeMethod(explicit_ordinal=42)
+    ]
+    ScrambleMethodOrdinals([interface], "foo".encode('utf-8'))
+    # These next three values are hard-coded. If the generation algorithm
+    # changes from being based on sha256(seed + interface.name + str(i)) then
+    # these numbers will obviously need to change too.
+    #
+    # Note that hashlib.sha256('fooRendererConfiguration1').digest()[:4] is
+    # '\xa5\xbc\xf9\xca' and that hex(1257880741) = '0x4af9bca5'. The
+    # difference in 0x4a vs 0xca is because we only take 31 bits.
+    self.assertEqual(interface.methods[0].ordinal, 1257880741)
+    self.assertEqual(interface.methods[1].ordinal, 631133653)
+    self.assertEqual(interface.methods[2].ordinal, 549336076)
+
+    # Explicit method ordinals should not be scrambled.
+    self.assertEqual(interface.methods[3].ordinal, 42)
+
+
+if __name__ == "__main__":
+  unittest.main()
diff --git a/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py b/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py
new file mode 100755
index 00000000..15f0e3ba
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/mojom_types_downgrader.py
@@ -0,0 +1,119 @@
+#!/usr/bin/env python
+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Downgrades *.mojom files to the old mojo types for remotes and receivers."""
+
+import argparse
+import fnmatch
+import os
+import re
+import shutil
+import sys
+import tempfile
+
+# List of patterns and replacements to match and use against the contents of a
+# mojo file. Each replacement string will be used with Python string's format()
+# function, so the '{}' substring is used to mark where the mojo type should go.
+_MOJO_REPLACEMENTS = {
+    r'pending_remote': r'{}',
+    r'pending_receiver': r'{}&',
+    r'pending_associated_remote': r'associated {}',
+    r'pending_associated_receiver': r'associated {}&',
+}
+
+# Pre-compiled regular expression that matches against any of the replacements.
+_REGEXP_PATTERN = re.compile(
+    r'|'.join(
+        ['{}\s*<\s*(.*?)\s*>'.format(k) for k in _MOJO_REPLACEMENTS.keys()]),
+    flags=re.DOTALL)
+
+
+def ReplaceFunction(match_object):
+  """Returns the right replacement for the string matched against the regexp."""
+  for index, (match, repl) in enumerate(_MOJO_REPLACEMENTS.items(), 1):
+    if match_object.group(0).startswith(match):
+      return repl.format(match_object.group(index))
+
+
+def DowngradeFile(path, output_dir=None):
+  """Downgrades the mojom file specified by |path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  # Use a temporary file to dump the new contents after replacing the patterns.
+  with open(path) as src_mojo_file:
+    with tempfile.NamedTemporaryFile(mode='w', delete=False) as tmp_mojo_file:
+      tmp_contents = _REGEXP_PATTERN.sub(ReplaceFunction, src_mojo_file.read())
+      tmp_mojo_file.write(tmp_contents)
+
+  # Files should be placed in the desired output directory
+  if output_dir:
+    output_filepath = os.path.join(output_dir, os.path.basename(path))
+    if not os.path.exists(output_dir):
+      os.makedirs(output_dir)
+  else:
+    output_filepath = path
+
+  # Write the new contents preserving the original file's attributes.
+  shutil.copystat(path, tmp_mojo_file.name)
+  shutil.move(tmp_mojo_file.name, output_filepath)
+
+  # Make sure to "touch" the new file so that access, modify and change times
+  # are always newer than the source file's, otherwise Modify time will be kept
+  # as per the call to shutil.copystat(), causing unnecessary generations of the
+  # output file in subsequent builds due to ninja considering it dirty.
+  os.utime(output_filepath, None)
+
+
+def DowngradeDirectory(path, output_dir=None):
+  """Downgrades mojom files inside directory |path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  # We don't have recursive glob.glob() nor pathlib.Path.rglob() in Python 2.7
+  mojom_filepaths = []
+  for dir_path, _, filenames in os.walk(path):
+    for filename in fnmatch.filter(filenames, "*mojom"):
+      mojom_filepaths.append(os.path.join(dir_path, filename))
+
+  for path in mojom_filepaths:
+    absolute_dirpath = os.path.dirname(os.path.abspath(path))
+    if output_dir:
+      dest_dirpath = output_dir + absolute_dirpath
+    else:
+      dest_dirpath = absolute_dirpath
+    DowngradeFile(path, dest_dirpath)
+
+
+def DowngradePath(src_path, output_dir=None):
+  """Downgrades the mojom files pointed by |src_path| to the old mojo types.
+
+  Optionally pass |output_dir| to place the result under a separate output
+  directory, preserving the relative path to the file included in |path|.
+  """
+  if os.path.isdir(src_path):
+    DowngradeDirectory(src_path, output_dir)
+  elif os.path.isfile(src_path):
+    DowngradeFile(src_path, output_dir)
+  else:
+    print(">>> {} not pointing to a valid file or directory".format(src_path))
+    sys.exit(1)
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Downgrade *.mojom files to use the old mojo types.")
+  parser.add_argument(
+      "srcpath", help="path to the file or directory to apply the conversion")
+  parser.add_argument(
+      "--outdir", help="the directory to place the converted file(s) under")
+  args = parser.parse_args()
+
+  DowngradePath(args.srcpath, args.outdir)
+
+
+if __name__ == "__main__":
+  sys.exit(main())
diff --git a/utils/ipc/mojo/public/tools/bindings/validate_typemap_config.py b/utils/ipc/mojo/public/tools/bindings/validate_typemap_config.py
new file mode 100755
index 00000000..f1783d59
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/bindings/validate_typemap_config.py
@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+# Copyright 2020 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import argparse
+import json
+import os
+import re
+import sys
+
+
+def CheckCppTypemapConfigs(target_name, config_filename, out_filename):
+  _SUPPORTED_CONFIG_KEYS = set([
+      'types', 'traits_headers', 'traits_private_headers', 'traits_sources',
+      'traits_deps', 'traits_public_deps'
+  ])
+  _SUPPORTED_TYPE_KEYS = set([
+      'mojom', 'cpp', 'copyable_pass_by_value', 'force_serialize', 'hashable',
+      'move_only', 'nullable_is_same_type'
+  ])
+  with open(config_filename, 'r') as f:
+    for config in json.load(f):
+      for key in config.keys():
+        if key not in _SUPPORTED_CONFIG_KEYS:
+          raise ValueError('Invalid typemap property "%s" when processing %s' %
+                           (key, target_name))
+
+      types = config.get('types')
+      if not types:
+        raise ValueError('Typemap for %s must specify at least one type to map'
+                         % target_name)
+
+      for entry in types:
+        for key in entry.keys():
+          if key not in _SUPPORTED_TYPE_KEYS:
+            raise IOError(
+                'Invalid type property "%s" in typemap for "%s" on target %s' %
+                (key, entry.get('mojom', '(unknown)'), target_name))
+
+  with open(out_filename, 'w') as f:
+    f.truncate(0)
+
+
+def main():
+  parser = argparse.ArgumentParser()
+  _, args = parser.parse_known_args()
+  if len(args) != 3:
+    print('Usage: validate_typemap_config.py target_name config_filename '
+          'stamp_filename')
+    sys.exit(1)
+
+  CheckCppTypemapConfigs(args[0], args[1], args[2])
+
+
+if __name__ == '__main__':
+  main()