Oilpan: Prepare to move ImageLoader and its subclasses to Oilpan heap.

Source/core/loader/ImageLoader.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 37 matching lines @@
     ImageLoaderClient() { }
 };
 
 class Element;
 class ImageLoader;
 class RenderImageResource;
 
 template<typename T> class EventSender;
 typedef EventSender<ImageLoader> ImageEventSender;
 
-class ImageLoader : public ImageResourceClient {
+class ImageLoader : public NoBaseWillBeGarbageCollectedFinalized<ImageLoader>, public ImageResourceClient {
 public:
     explicit ImageLoader(Element*);
     virtual ~ImageLoader();
+    void trace(Visitor*);
 
     enum LoadType {
         LoadNormally,
         ForceLoadImmediately
     };
 
     // This function should be called when the element is attached to a document; starts
     // loading if a load hasn't already been started.
     void updateFromElement(LoadType = LoadNormally);
 
@@ skipping 54 matching lines @@
     void timerFired(Timer<ImageLoader>*);
 
     KURL imageURL() const;
 
     // Used to determine whether to immediately initiate the load
     // or to schedule a microtask.
     bool shouldLoadImmediately(const KURL&) const;
 
     void willRemoveClient(ImageLoaderClient&);
 
-    Element* m_element;
+    RawPtrWillBeMember<Element> m_element;
     ResourcePtr<ImageResource> m_image;
 #if ENABLE(OILPAN)
+    // FIXME: Oilpan: We might be able to remove this hack when
+    // ImageResourceClient is traceable.
+    GC_PLUGIN_IGNORE("http://crbug.com/353083")
+    Persistent<ImageLoader> m_keepAlive;
+
     class ImageLoaderClientRemover {
     public:
         ImageLoaderClientRemover(ImageLoader& loader, ImageLoaderClient& client) : m_loader(loader), m_client(client) { }
         ~ImageLoaderClientRemover();
 
     private:
         ImageLoader& m_loader;
         ImageLoaderClient& m_client;
     };
     friend class ImageLoaderClientRemover;
+    // Oilpan: This ImageLoader object must outlive its clients because they
+    // need to call ImageLoader::willRemoveClient before they die.
+    GC_PLUGIN_IGNORE("http://crbug.com/353083")
     PersistentHeapHashMap<WeakMember<ImageLoaderClient>, OwnPtr<ImageLoaderClientRemover> > m_clients;

[haraken, 2014/06/09 11:12:34]

Why does this need to be a Persistent? It looks strange to trace a persistent
handle.

[tkent, 2014/06/10 01:43:09]

The comment above explains it.
Tracing this is my bad.  I'll remove it.

 #else
     HashSet<ImageLoaderClient*> m_clients;
 #endif
     Timer<ImageLoader> m_derefElementTimer;
     AtomicString m_failedLoadURL;
     WeakPtr<Task> m_pendingTask; // owned by Microtask
     OwnPtr<IncrementLoadEventDelayCount> m_delayLoad;
     bool m_hasPendingLoadEvent : 1;
     bool m_hasPendingErrorEvent : 1;
     bool m_imageComplete : 1;
     bool m_loadManually : 1;
     bool m_elementIsProtected : 1;
     unsigned m_highPriorityClientCount;
 };
 
 }
 
 #endif