1 files changed, 11 insertions, 10 deletions
diff --git a/utils/ipc/mojo/public/tools/mojom/mojom/parse/conditional_features.py b/utils/ipc/mojo/public/tools/mojom/mojom/parse/conditional_features.py
index 3cb73c5d..9687edbf 100644
--- a/utils/ipc/mojo/public/tools/mojom/mojom/parse/conditional_features.py
+++ b/utils/ipc/mojo/public/tools/mojom/mojom/parse/conditional_features.py
@@ -1,4 +1,4 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
+# Copyright 2018 The Chromium Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 """Helpers for processing conditionally enabled features in a mojom."""
@@ -17,8 +17,10 @@ class EnableIfError(Error):
 def _IsEnabled(definition, enabled_features):
   """Returns true if a definition is enabled.
 
-  A definition is enabled if it has no EnableIf attribute, or if the value of
-  the EnableIf attribute is in enabled_features.
+  A definition is enabled if it has no EnableIf/EnableIfNot attribute.
+  It is retained if it has an EnableIf attribute and the attribute is in
+  enabled_features. It is retained if it has an EnableIfNot attribute and the
+  attribute is not in enabled features.
   """
   if not hasattr(definition, "attribute_list"):
     return True
@@ -27,17 +29,19 @@ def _IsEnabled(definition, enabled_features):
 
   already_defined = False
   for a in definition.attribute_list:
-    if a.key == 'EnableIf':
+    if a.key == 'EnableIf' or a.key == 'EnableIfNot':
       if already_defined:
         raise EnableIfError(
             definition.filename,
-            "EnableIf attribute may only be defined once per field.",
+            "EnableIf/EnableIfNot attribute may only be set once per field.",
             definition.lineno)
       already_defined = True
 
   for attribute in definition.attribute_list:
     if attribute.key == 'EnableIf' and attribute.value not in enabled_features:
       return False
+    if attribute.key == 'EnableIfNot' and attribute.value in enabled_features:
+      return False
   return True
 
 
@@ -56,15 +60,12 @@ def _FilterDefinition(definition, enabled_features):
   """Filters definitions with a body."""
   if isinstance(definition, ast.Enum):
     _FilterDisabledFromNodeList(definition.enum_value_list, enabled_features)
-  elif isinstance(definition, ast.Interface):
-    _FilterDisabledFromNodeList(definition.body, enabled_features)
   elif isinstance(definition, ast.Method):
     _FilterDisabledFromNodeList(definition.parameter_list, enabled_features)
     _FilterDisabledFromNodeList(definition.response_parameter_list,
                                 enabled_features)
-  elif isinstance(definition, ast.Struct):
-    _FilterDisabledFromNodeList(definition.body, enabled_features)
-  elif isinstance(definition, ast.Union):
+  elif isinstance(definition,
+                  (ast.Interface, ast.Struct, ast.Union, ast.Feature)):
     _FilterDisabledFromNodeList(definition.body, enabled_features)