Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/WebGLContextGroup.h

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 #ifndef WebGLContextGroup_h
 #define WebGLContextGroup_h
 
 #include "core/html/canvas/WebGLRenderingContextBase.h"
+#include "platform/heap/Handle.h"
 #include "wtf/HashSet.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 class WebGraphicsContext3D;
 }
 
 namespace WebCore {
 
 class WebGLExtension;
 class WebGLSharedObject;
 class WebGLRenderingContextBase;
 
 typedef int ExceptionCode;
 
-class WebGLContextGroup FINAL : public RefCounted<WebGLContextGroup> {
+class WebGLContextGroup FINAL : public RefCountedWillBeGarbageCollected<WebGLContextGroup> {
+    DECLARE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(WebGLContextGroup);
 public:
-    static PassRefPtr<WebGLContextGroup> create();
-    ~WebGLContextGroup();
+    static PassRefPtrWillBeRawPtr<WebGLContextGroup> create();
 
     void addContext(WebGLRenderingContextBase*);
     void removeContext(WebGLRenderingContextBase*);

[haraken, 2014/07/02 07:47:38]

Can we add #if !ENABLE(OILPAN) to this method?

[sof, 2014/07/02 11:43:52]

I don't think that's workable overall as contexts will have to be explicitly
managed by the WebGLContextGroup, so as to reliably be able to release its
'group objects' (and in turn, have them reliably delete their underlying
resource objects.)

 
     void addObject(WebGLSharedObject*);
     void removeObject(WebGLSharedObject*);
 
     blink::WebGraphicsContext3D* getAWebGraphicsContext3D();
 
     void loseContextGroup(WebGLRenderingContextBase::LostContextMode);
 
+    void trace(Visitor*);
+    void clearWeakMembers(Visitor*);
+
   private:
     friend class WebGLObject;
 
     WebGLContextGroup();
 
     void detachAndRemoveAllObjects();
 
-    HashSet<WebGLRenderingContextBase*> m_contexts;
-    HashSet<WebGLSharedObject*> m_groupObjects;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<WebGLRenderingContextBase> > m_contexts;
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<WebGLSharedObject> > m_groupObjects;
+
+#if ENABLE(OILPAN)
+    // Oilpan: Weak context references are kept, so in order to handle
+    // the case where all contexts fall away and the group objects
+    // will have to be flushed, we save away a 3D context object during
+    // tracing. It will be used during the weak callback only and cleared
+    // then.
+    blink::WebGraphicsContext3D* m_savedContext;
+#endif
 };
 
 } // namespace WebCore
 
 #endif // WebGLContextGroup_h