[WebGL-blink] Add test function to force fail the webgl-context

public/web/WebView.h

 /*
  * Copyright (C) 2009, 2010, 2011, 2012 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 475 matching lines @@
 
     // i18n -----------------------------------------------------------------
 
     // Inform the WebView that the accept languages have changed.
     // If the WebView wants to get the accept languages value, it will have
     // to call the WebViewClient::acceptLanguages().
     virtual void acceptLanguagesChanged() = 0;
 
     // Testing functionality for TestRunner ---------------------------------
 
+    // Force the webgl context to fail so that webglcontextcreationerror
+    // event gets generated/tested.
+    virtual void forceNextWebGLContextCreationToFail() = 0;
+
 protected:
     ~WebView() {}
 };
 
 } // namespace blink
 
 #endif