Limit the number of WebGL contexts that are active at any given time

Source/core/html/canvas/WebGLRenderingContext.h

Index: Source/core/html/canvas/WebGLRenderingContext.h
diff --git a/Source/core/html/canvas/WebGLRenderingContext.h b/Source/core/html/canvas/WebGLRenderingContext.h
index 6e6fe0a668ef4ad305fb0af99469e7576373ccc2..94179327d6af746a3d1351a92b9dd79309667045 100644
--- a/Source/core/html/canvas/WebGLRenderingContext.h
+++ b/Source/core/html/canvas/WebGLRenderingContext.h
@@ -324,6 +324,9 @@ public:
     virtual bool hasPendingActivity() const;
     virtual void stop();
 
+    static void forciblyLoseOldestContext();
+    static IntSize oldestContextSize();
+
   private:
     friend class EXTDrawBuffers;
     friend class WebGLFramebuffer;
@@ -782,6 +785,13 @@ public:
     bool supportsDrawBuffers();
 
     friend class WebGLStateRestorer;
+
+    static Vector<WebGLRenderingContext*>& activeContexts();
+    static Vector<WebGLRenderingContext*>& forciblyEvictedContexts();
+
+    static void activateContext(WebGLRenderingContext*);
+    static void deactivateContext(WebGLRenderingContext*, bool addToInactiveList);
+    static void willDestroyContext(WebGLRenderingContext*);
 };
 
 } // namespace WebCore