[Oilpan] Add a GC_PLUGIN_IGNORE with a TODO comment

Source/web/WebDevToolsFrontendImpl.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 44 matching lines @@
 
     void sendMessageToEmbedder(const WTF::String&) override;
 
     bool isUnderTest() override;
 
     void showContextMenu(LocalFrame*, float x, float y, PassRefPtrWillBeRawPtr<ContextMenuProvider>) override;
 
     void setInjectedScriptForOrigin(const String& origin, const String& source) override;
 
 private:
-    WebLocalFrameImpl* m_webFrame;
+    RawPtrWillBeWeakPersistent<WebLocalFrameImpl> m_webFrame;

[haraken, 2015/08/27 09:13:49]

This pointer looks nasty...

- We shouldn't use WeakPersistent for a pointer that doesn't have a weak
semantics (m_webFrame is a strong back pointer to the LocalFrameImpl). Thus we
shouldn't use a WeakPersistent here.

- It is not easy to move WebDevToolsFrontendImpl to the heap and use Member,
because the WebDevToolsFrontendImpl is passed over to the chromium side.

- In the first place, it's not clear to me why the raw m_webFrame pointer is
safe. How is it guaranteed that the raw pointer doesn't become stale?

     WebDevToolsFrontendClient* m_client;
     RefPtrWillBePersistent<DevToolsHost> m_devtoolsHost;
     typedef HashMap<String, String> InjectedScriptForOriginMap;
     InjectedScriptForOriginMap m_injectedScriptForOrigin;
 };
 
 } // namespace blink
 
 #endif