Implement WEBGL_shared_resources

Source/core/html/canvas/WebGLContextGroup.h

Index: Source/core/html/canvas/WebGLContextGroup.h
diff --git a/Source/core/html/canvas/WebGLContextGroup.h b/Source/core/html/canvas/WebGLContextGroup.h
index e888083f38fd8bcf2064758872fc00d3cf686e0f..7c46e91ad65dba6b420f5b37bc90e8896bd684ce 100644
--- a/Source/core/html/canvas/WebGLContextGroup.h
+++ b/Source/core/html/canvas/WebGLContextGroup.h
@@ -45,7 +45,8 @@ public:
     static PassRefPtr<WebGLContextGroup> create();
     virtual ~WebGLContextGroup();
 
-    void addContext(WebGLRenderingContext*);
+    // Adds the context to this group and returns a context index of the context.

[Ken Russell (switch to Gerrit), 2013/06/19 03:51:24]

Is the context index used anywhere? It looks like it's ignored at the call site.

[greggman, 2013/06/21 19:54:21]

Done.

+    unsigned addContext(WebGLRenderingContext*);
     void removeContext(WebGLRenderingContext*);
 
     void addObject(WebGLSharedObject*);
@@ -55,6 +56,13 @@ public:
 
     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;
 
@@ -62,6 +70,9 @@ public:
 
     void detachAndRemoveAllObjects();
 
+    unsigned m_contextCreationCount;
+    long m_acquireRequestCount;
+
     HashSet<WebGLRenderingContext*> m_contexts;
     HashSet<WebGLSharedObject*> m_groupObjects;
 };