Oilpan: have History on the heap by default.

Source/core/frame/History.h

 /*
  * Copyright (C) 2007 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 #ifndef History_h
 #define History_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/core/v8/SerializedScriptValue.h"
 #include "core/loader/FrameLoaderTypes.h"
 #include "core/frame/DOMWindowProperty.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
-#include "wtf/PassRefPtr.h"
-#include "wtf/RefCounted.h"
 
 namespace blink {
 
 class LocalFrame;
 class KURL;
 class ExecutionContext;
 class ExceptionState;
 
-class History final : public RefCountedWillBeGarbageCollectedFinalized<History>, public ScriptWrappable, public DOMWindowProperty {
+class History final : public GarbageCollectedFinalized<History>, public ScriptWrappable, public DOMWindowProperty {
     DEFINE_WRAPPERTYPEINFO();
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(History);

[haraken, 2015/04/24 12:43:52]

WILL_BE_USING_GARBAGE_COLLECTED_MIXIN => USING_GARBAGE_COLLECTED_MIXIN

Here, again, we need to make sure that it is safe to move History to Oilpan
without moving DOMWindowProperty to Oilpan.

The only guy who traces DOMWindowProperty is LocalDOMWindow, and the
LocalDOMWindow is tracing the DOMWindowProperty weakly (not strongly). Thus it
is safe to move History to Oilpan without moving DOMWindowProperty as long as we
keep the pointer-clear-out code as is.

So this CL looks safe.

[sof, 2015/04/24 12:46:41]

I'm not quite sure what to make of the "=>" at the top -- it needs to be
WILL_BE, as DOMWindowProperty is WillBeGarbageCollectedMixin.

[haraken, 2015/04/24 12:47:28]

ah, right. We need to drop the WillBe when dropping the WillBe from
DOMWindowProperty.

 public:
-    static PassRefPtrWillBeRawPtr<History> create(LocalFrame* frame)
+    static History* create(LocalFrame* frame)
     {
-        return adoptRefWillBeNoop(new History(frame));
+        return new History(frame);
     }
 
     unsigned length() const;
     SerializedScriptValue* state();
 
     void back(ExecutionContext*);
     void forward(ExecutionContext*);
     void go(ExecutionContext*, int distance);
 
     void pushState(PassRefPtr<SerializedScriptValue> data, const String& title, const String& url, ExceptionState& exceptionState)
@@ skipping 19 matching lines @@
     KURL urlForState(const String& url);
 
     SerializedScriptValue* stateInternal() const;
 
     RefPtr<SerializedScriptValue> m_lastStateObjectRequested;
 };
 
 } // namespace blink
 
 #endif // History_h