[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<Member<WebGLSharedObject>> m_groupObjects;

[Ken Russell (switch to Gerrit), 2015/08/01 00:11:56]

I think we should file a bug about removing these m_groupObjects, similarly to
comment in WebGLRenderingContextBase about removing m_contextObjects. I think
that with sufficient modeling of the OpenGL state so that live WebGLObjects
don't get accidentally GC'd, we ought to be able to avoid these weak references
from the WebGLRenderingContextBase to the objects it's allocated. Do you agree?

[peria, 2015/08/03 09:00:35]

I agree to remove them, but I think it is not good to make those reference map
strong references.
I changed m_groupObjects a weak reference map.

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