Add [CachedAccessor] attribute to cache (almost) constant accessors (window.document).

third_party/WebKit/Source/bindings/core/v8/V8DOMConfiguration.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 47 matching lines @@
     };
 
     enum HolderCheckConfiguration {
         CheckHolder,
         DoNotCheckHolder,
     };
 
     typedef v8::experimental::FastAccessorBuilder* (*FastAccessorBuilderCallback)(v8::Isolate*,
         v8::FunctionCallback); // Default (slow) callback.
 
+    typedef v8::Local<v8::Private> (*PrivatePropertyCallback)(v8::Isolate*);

[haraken, 2016/09/20 14:15:03]

PrivatePropertyCallback => CachedAccessorCallback ?

+
     // AttributeConfiguration translates into calls to SetNativeDataProperty() on either
     // the instance or the prototype ObjectTemplate, based on |instanceOrPrototypeConfiguration|.
     struct AttributeConfiguration {
         AttributeConfiguration& operator=(const AttributeConfiguration&) = delete;
         DISALLOW_NEW();
         const char* const name;
         v8::AccessorNameGetterCallback getter;
         v8::AccessorNameSetterCallback setter;
         v8::AccessorNameGetterCallback getterForMainWorld;
         v8::AccessorNameSetterCallback setterForMainWorld;
-        // TODO(vogelheim): Figure out how to remove this.
+
+        // TODO(peterssen|vogelheim): Figure out how to remove this.
         FastAccessorBuilderCallback fastGetter;
+        // TODO(peterssen|vogelheim): This has to be removed too since it's only used in accessors.
+        PrivatePropertyCallback cachePropertyCallback; // The accessor's 'result' is stored in a private property.

[haraken, 2016/09/20 14:15:03]

cachedAccessorCallback ?

+
         const WrapperTypeInfo* data;
         unsigned settings : 8; // v8::AccessControl
         unsigned attribute : 8; // v8::PropertyAttribute
         unsigned exposeConfiguration : 1; // ExposeConfiguration
         unsigned propertyLocationConfiguration : 3; // PropertyLocationConfiguration
         unsigned holderCheckConfiguration : 1; // HolderCheckConfiguration
     };
 
     static void installAttributes(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::ObjectTemplate> instanceTemplate, v8::Local<v8::ObjectTemplate> prototypeTemplate, const AttributeConfiguration*, size_t attributeCount);
 
     static void installAttribute(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::ObjectTemplate> instanceTemplate, v8::Local<v8::ObjectTemplate> prototypeTemplate, const AttributeConfiguration&);
 
     static void installAttribute(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::Object> instance, v8::Local<v8::Object> prototype, const AttributeConfiguration&);
 
     // AccessorConfiguration translates into calls to SetAccessorProperty()
     // on prototype ObjectTemplate.
     struct AccessorConfiguration {
         AccessorConfiguration& operator=(const AccessorConfiguration&) = delete;
         DISALLOW_NEW();
         const char* const name;
         v8::FunctionCallback getter;
         v8::FunctionCallback setter;
         v8::FunctionCallback getterForMainWorld;
         v8::FunctionCallback setterForMainWorld;
         FastAccessorBuilderCallback fastGetter;
+        PrivatePropertyCallback cachePropertyCallback; // The accessor's 'result' is stored in a private property.

[haraken, 2016/09/20 14:15:03]

cachedAccessorCallback ?

         const WrapperTypeInfo* data;
         unsigned settings : 8; // v8::AccessControl
         unsigned attribute : 8; // v8::PropertyAttribute
         unsigned exposeConfiguration : 1; // ExposeConfiguration
         unsigned propertyLocationConfiguration : 3; // PropertyLocationConfiguration
         unsigned holderCheckConfiguration : 1; // HolderCheckConfiguration
     };
 
     static void installAccessors(v8::Isolate*, const DOMWrapperWorld&, v8::Local<v8::ObjectTemplate> instanceTemplate, v8::Local<v8::ObjectTemplate> prototypeTemplate, v8::Local<v8::FunctionTemplate> interfaceTemplate, v8::Local<v8::Signature>, const AccessorConfiguration*, size_t accessorCount);
 
@@ skipping 90 matching lines @@
     static v8::Local<v8::FunctionTemplate> domClassTemplate(v8::Isolate*, const DOMWrapperWorld&, WrapperTypeInfo*, InstallTemplateFunction);
 
     // Sets the class string of platform objects, interface prototype objects, etc.
     // See also http://heycam.github.io/webidl/#dfn-class-string
     static void setClassString(v8::Isolate*, v8::Local<v8::ObjectTemplate>, const char* classString);
 };
 
 } // namespace blink
 
 #endif // V8DOMConfiguration_h