Merge 185069 "Enforce context refrence guards in WebGL extensions."

Source/core/html/canvas/WebGLLoseContext.cpp

 /*
  * Copyright (C) 2010 Google 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
@@ skipping 40 matching lines @@
     return WebGLLoseContextName;
 }
 
 PassRefPtrWillBeRawPtr<WebGLLoseContext> WebGLLoseContext::create(WebGLRenderingContextBase* context)
 {
     return adoptRefWillBeNoop(new WebGLLoseContext(context));
 }
 
 void WebGLLoseContext::loseContext()
 {
-    if (!isLost())
-        m_context->forceLostContext(WebGLRenderingContextBase::WebGLLoseContextLostContext, WebGLRenderingContextBase::Manual);
+    WebGLExtensionScopedContext scoped(this);
+    if (!scoped.isLost())
+        scoped.context()->forceLostContext(WebGLRenderingContextBase::WebGLLoseContextLostContext, WebGLRenderingContextBase::Manual);
 }
 
 void WebGLLoseContext::restoreContext()
 {
-    if (!isLost())
-        m_context->forceRestoreContext();
+    WebGLExtensionScopedContext scoped(this);
+    if (!scoped.isLost())
+        scoped.context()->forceRestoreContext();
 }
 
 bool WebGLLoseContext::supported(WebGLRenderingContextBase*)
 {
     return true;
 }
 
 const char* WebGLLoseContext::extensionName()
 {
     return "WEBGL_lose_context";
 }
 
 } // namespace blink