Revert of Make lost context and error message callbacks on GpuControl go to client

mojo/gles2/gles2_context.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_GLES2_GLES2_CONTEXT_H_
 #define MOJO_GLES2_GLES2_CONTEXT_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "gpu/command_buffer/client/gles2_implementation.h"
 #include "mojo/gles2/command_buffer_client_impl.h"
 #include "mojo/public/c/gles2/gles2.h"
 
 struct MojoGLES2ContextPrivate {};
 
 namespace gpu {
 class TransferBuffer;
 namespace gles2 {
 class GLES2CmdHelper;
 class GLES2Implementation;
 }
 }
 
 namespace gles2 {
 
-class GLES2Context : public MojoGLES2ContextPrivate {
+class GLES2Context : public CommandBufferDelegate,
+                     public MojoGLES2ContextPrivate {
  public:
   explicit GLES2Context(const std::vector<int32_t>& attribs,
                         mojo::ScopedMessagePipeHandle command_buffer_handle,
                         MojoGLES2ContextLost lost_callback,
                         void* closure);
-  virtual ~GLES2Context();
+  ~GLES2Context() override;
   bool Initialize();
 
   gpu::gles2::GLES2Interface* interface() const {
     return implementation_.get();
   }
   gpu::ContextSupport* context_support() const { return implementation_.get(); }
 
  private:
-  void OnLostContext();
+  void ContextLost() override;
 
   CommandBufferClientImpl command_buffer_;
   scoped_ptr<gpu::gles2::GLES2CmdHelper> gles2_helper_;
   scoped_ptr<gpu::TransferBuffer> transfer_buffer_;
   scoped_ptr<gpu::gles2::GLES2Implementation> implementation_;
   MojoGLES2ContextLost lost_callback_;
   void* closure_;
 
   DISALLOW_COPY_AND_ASSIGN(GLES2Context);
 };
 
 }  // namespace gles2
 
 #endif  // MOJO_GLES2_GLES2_CONTEXT_H_