Use new phantom handles for ScriptWrappable.

Source/bindings/core/v8/ScriptWrappable.h

 /*
  * Copyright (C) 2010 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 67 matching lines @@
     virtual v8::Handle<v8::Object> associateWithWrapper(v8::Isolate*, const WrapperTypeInfo*, v8::Handle<v8::Object> wrapper);
 
     void setWrapper(v8::Handle<v8::Object> wrapper, v8::Isolate* isolate, const WrapperTypeInfo* wrapperTypeInfo)
     {
         ASSERT(!containsWrapper());
         if (!*wrapper)
             return;
         RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(toScriptWrappable(wrapper) == this);
         m_wrapper.Reset(isolate, wrapper);
         wrapperTypeInfo->configureWrapper(&m_wrapper);
-        m_wrapper.SetWeak(this, &setWeakCallback);
+        m_wrapper.SetPhantom(&setWeakCallback, v8DOMWrapperTypeIndex, v8DOMWrapperObjectIndex);
         ASSERT(containsWrapper());
     }
 
     v8::Local<v8::Object> newLocalWrapper(v8::Isolate* isolate) const
     {
         return v8::Local<v8::Object>::New(isolate, m_wrapper);
     }
 
     bool isEqualTo(const v8::Local<v8::Object>& other) const
     {
@@ skipping 53 matching lines @@
     // With Oilpan we don't need a ScriptWrappable destructor.
     //
     // - 'RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(!containsWrapper())' is not needed
     // because Oilpan is not using reference counting at all. If containsWrapper() is true,
     // it means that ScriptWrappable still has a wrapper. In this case, the destructor
     // must not be called since the wrapper has a persistent handle back to this ScriptWrappable object.
     // Assuming that Oilpan's GC is correct (If we cannot assume this, a lot of more things are
     // already broken), we must not hit the RELEASE_ASSERT.
 
 private:
-    void disposeWrapper(v8::Local<v8::Object> wrapper)
+    static void setWeakCallback(const v8::InternalFieldsCallbackData<WrapperTypeInfo, ScriptWrappable>& data)
     {
-        ASSERT(containsWrapper());
-        ASSERT(wrapper == m_wrapper);
-        m_wrapper.Reset();
-    }
-
-    static void setWeakCallback(const v8::WeakCallbackData<v8::Object, ScriptWrappable>& data)
-    {
-        data.GetParameter()->disposeWrapper(data.GetValue());
-
         // FIXME: I noticed that 50%~ of minor GC cycle times can be consumed
         // inside data.GetParameter()->deref(), which causes Node destructions. We should
         // make Node destructions incremental.
-        releaseObject(data.GetValue());
+        WrapperTypeInfo* wrapperTypeInfo = reinterpret_cast<WrapperTypeInfo*>(data.GetInternalField1());
+        ScriptWrappable* scriptWrappable = reinterpret_cast<ScriptWrappable*>(data.GetInternalField2());
+        scriptWrappable->m_wrapper.Empty();

[haraken, 2015/01/07 15:51:41]

Do we go with Empty, whereas other similar V8 APIs are named Clear or Reset?

[Erik Corry Chromium.org, 2015/01/07 16:07:56]

Empty is to match the preexisting IsEmpty().  Reset is different in that it
tears down the weak handle, which isn't what we want here, since it is already
in the process of being torn down.

+        wrapperTypeInfo->derefObject(scriptWrappable);
     }
 
     v8::Persistent<v8::Object> m_wrapper;
 };
 
 // Defines 'wrapperTypeInfo' virtual method which returns the WrapperTypeInfo of
 // the instance. Also declares a static member of type WrapperTypeInfo, of which
 // the definition is given by the IDL code generator.
 //
 // All the derived classes of ScriptWrappable, regardless of directly or
@@ skipping 23 matching lines @@
     { \
         ASSERT_NOT_REACHED(); \
         return 0; \
     } \
 private: \
     typedef void end_of_define_wrappertypeinfo_not_reached_t
 
 } // namespace blink
 
 #endif // ScriptWrappable_h