[Oilpan] Migrate classes under module/webgl onto oilpan heap

Source/modules/webgl/WebGLContextGroup.h

 /*
  * Copyright (C) 2011 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 53 matching lines @@
 
     void detachAndRemoveAllObjects();
 
     // FIXME: Oilpan: this object is not on the heap, but keeps bare
     // pointers to garbage collected objects in the two hash sets
     // below. The objects are responsible for managing their
     // registration with WebGLContextGroup, and vice versa, the
     // WebGLContextGroup takes care of detaching the group objects if
     // the set of WebGLRenderingContextBase contexts becomes empty.
     HashSet<WebGLRenderingContextBase*> m_contexts;
-    HashSet<WebGLSharedObject*> m_groupObjects;
+    PersistentHeapHashSet<WeakMember<WebGLSharedObject>> m_groupObjects;

[haraken, 2015/08/04 00:06:52]

It looks harmless to make these raw pointers weak, but the handling of the raw
pointers are complicated. Let's keep them as raw pointers in this CL and address
them in a follow-up CL.

[Ken Russell (switch to Gerrit), 2015/08/04 00:34:10]

+1 for keeping the behavioral changes as simple as possible in this CL.
Appreciate your continued work on this after this CL lands.

[peria, 2015/08/04 09:10:25]

Done.

 };
 
 } // namespace blink
 
 #endif // WebGLContextGroup_h