[oilpan]: optimize the way we allocate persistent handles in wrappers.

Source/bindings/core/v8/custom/V8InjectedScriptManager.cpp

 /*
  * 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:
  *
  *     * 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 54 matching lines @@
 {
     ASSERT(host);
 
     v8::Handle<v8::Object> wrapper = V8DOMWrapper::createWrapper(creationContext, &V8InjectedScriptHost::wrapperTypeInfo, V8InjectedScriptHost::toInternalPointer(host.get()), isolate);
     if (UNLIKELY(wrapper.IsEmpty()))
         return wrapper;
 
     // Create a weak reference to the v8 wrapper of InspectorBackend to deref
     // InspectorBackend when the wrapper is garbage collected.
     InjectedScriptManager::CallbackData* callbackData = injectedScriptManager->createCallbackData(injectedScriptManager);
+#if ENABLE(OILPAN)
+    callbackData->hostPtr = new WrapperPersistent<InjectedScriptHost>(host.get());
+#else
     callbackData->host = host.get();

[zerny-chromium, 2014/09/01 14:13:37]

Is this field never used in the oilpan build?

[wibling-chromium, 2014/09/02 11:19:37]

No, AFAICT it is only used to keep the object alive.

+#endif
     callbackData->handle.set(isolate, wrapper);
     callbackData->handle.setWeak(callbackData, &InjectedScriptManager::setWeakCallback);
 
 #if ENABLE(OILPAN)
-    V8DOMWrapper::setNativeInfoWithPersistentHandle(wrapper, &V8InjectedScriptHost::wrapperTypeInfo, V8InjectedScriptHost::toInternalPointer(host), &callbackData->host);
+    V8DOMWrapper::setNativeInfoWithPersistentHandle(wrapper, &V8InjectedScriptHost::wrapperTypeInfo, V8InjectedScriptHost::toInternalPointer(host), callbackData->hostPtr);
 #else
     V8DOMWrapper::setNativeInfo(wrapper, &V8InjectedScriptHost::wrapperTypeInfo, V8InjectedScriptHost::toInternalPointer(host.get()));
 #endif
     ASSERT(V8DOMWrapper::isDOMWrapper(wrapper));
     return wrapper;
 }
 
 ScriptValue InjectedScriptManager::createInjectedScript(const String& scriptSource, ScriptState* inspectedScriptState, int id)
 {
     v8::Isolate* isolate = inspectedScriptState->isolate();
@@ skipping 36 matching lines @@
     return BindingSecurity::shouldAllowAccessToFrame(scriptState->isolate(), frame, DoNotReportSecurityError);
 }
 
 void InjectedScriptManager::setWeakCallback(const v8::WeakCallbackData<v8::Object, InjectedScriptManager::CallbackData>& data)
 {
     InjectedScriptManager::CallbackData* callbackData = data.GetParameter();
     callbackData->injectedScriptManager->removeCallbackData(callbackData);
 }
 
 } // namespace blink