Implement WEBGL_shared_resources

Source/core/html/canvas/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 27 matching lines @@
 class WebGLSharedObject;
 class WebGLRenderingContext;
 
 typedef int ExceptionCode;
 
 class WebGLContextGroup : public RefCounted<WebGLContextGroup> {
 public:
     static PassRefPtr<WebGLContextGroup> create();
     virtual ~WebGLContextGroup();
 
-    void addContext(WebGLRenderingContext*);
+    // Adds the context to this group and returns a context index of the context.
+    unsigned addContext(WebGLRenderingContext*);
     void removeContext(WebGLRenderingContext*);
 
     void addObject(WebGLSharedObject*);
     void removeObject(WebGLSharedObject*);
 
     GraphicsContext3D* getAGraphicsContext3D();
 
     void loseContextGroup(WebGLRenderingContext::LostContextMode);
 
+    // Problem with this is it won't work in workers. You need
+    // one object per worker per context group.
+    void flushOnContextSwitch(WebGLRenderingContext*);
+
+    long generateAcquireRequestId();
+    void cancelAcquireSharedResource(const WebGLRenderingContext*, long);
+
   private:
     friend class WebGLObject;
 
     WebGLContextGroup();
 
     void detachAndRemoveAllObjects();
 
+    unsigned m_contextCreationCount;
+    long m_acquireRequestCount;
+
     HashSet<WebGLRenderingContext*> m_contexts;
     HashSet<WebGLSharedObject*> m_groupObjects;
 };
 
 } // namespace WebCore
 
 #endif // WebGLContextGroup_h