Implement cross-origin attributes using access check interceptors.

third_party/WebKit/Source/bindings/core/v8/V8DOMWrapper.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 71 matching lines @@
   if (object->InternalFieldCount() < v8DefaultWrapperInternalFieldCount)
     return false;
 
   const WrapperTypeInfo* untrustedWrapperTypeInfo = toWrapperTypeInfo(object);
   V8PerIsolateData* perIsolateData = V8PerIsolateData::from(isolate);
   if (!(untrustedWrapperTypeInfo && perIsolateData))
     return false;
   return perIsolateData->hasInstance(untrustedWrapperTypeInfo, object);
 }
 
+void V8DOMWrapper::clearNativeInfo(v8::Isolate* isolate,
+                                   v8::Local<v8::Object> wrapper) {
+  DCHECK_GE(wrapper->InternalFieldCount(), 2);
+  int indices[] = {v8DOMWrapperObjectIndex, v8DOMWrapperTypeIndex};
+  void* values[] = {nullptr, nullptr};
+  wrapper->SetAlignedPointerInInternalFields(WTF_ARRAY_LENGTH(indices), indices,
+                                             values);
+}
+
 bool V8DOMWrapper::hasInternalFieldsSet(v8::Local<v8::Value> value) {
   if (value.IsEmpty() || !value->IsObject())
     return false;
   v8::Local<v8::Object> object = v8::Local<v8::Object>::Cast(value);
 
   if (object->InternalFieldCount() < v8DefaultWrapperInternalFieldCount)
     return false;
 
   const ScriptWrappable* untrustedScriptWrappable = toScriptWrappable(object);
   const WrapperTypeInfo* untrustedWrapperTypeInfo = toWrapperTypeInfo(object);
@@ skipping 47 matching lines @@
                                 isolate->GetCurrentContext()->Global(),
                                 isolate);
   LocalDOMWindow* callingWindow = currentDOMWindow(isolate);
   DOMWindow* targetWindow = toDOMWindow(m_context);
   exceptionState.throwSecurityError(
       targetWindow->sanitizedCrossDomainAccessErrorMessage(callingWindow),
       targetWindow->crossDomainAccessErrorMessage(callingWindow));
 }
 
 }  // namespace blink