Remove setErrorMessageCallback from WebGraphicsContext3D.

third_party/WebKit/public/platform/WebGraphicsContext3D.h

 /*
  * Copyright (C) 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 32 matching lines @@
 class WebGraphicsContext3D : public WebNonCopyable {
 public:
     class WebGraphicsContextLostCallback {
     public:
         virtual void onContextLost() = 0;
 
     protected:
         virtual ~WebGraphicsContextLostCallback() { }
     };
 
-    class WebGraphicsErrorMessageCallback {
-    public:
-        virtual void onErrorMessage(const WebString&, int) = 0;
-
-    protected:
-        virtual ~WebGraphicsErrorMessageCallback() { }
-    };
-
     // This destructor needs to be public so that using classes can destroy instances if initialization fails.
     virtual ~WebGraphicsContext3D() { }
-
-    virtual void setErrorMessageCallback(WebGraphicsErrorMessageCallback* callback) { }
 };
 
 } // namespace blink
 
 #endif