Revert of cc: Implement shared worker contexts.

content/renderer/gpu/mailbox_output_surface.h

 // Copyright (c) 2012 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 CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_
 #define CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_
 
 #include <queue>
 
 #include "base/memory/ref_counted.h"
@@ skipping 20 matching lines @@
       uint32 output_surface_id,
       const scoped_refptr<ContextProviderCommandBuffer>& context_provider,
       const scoped_refptr<ContextProviderCommandBuffer>&
           worker_context_provider,
       scoped_ptr<cc::SoftwareOutputDevice> software_device,
       scoped_refptr<FrameSwapMessageQueue> swap_frame_message_queue,
       cc::ResourceFormat format);
   ~MailboxOutputSurface() override;
 
   // cc::OutputSurface implementation.
-  void DetachFromClient() override;
   void EnsureBackbuffer() override;
   void DiscardBackbuffer() override;
   void Reshape(const gfx::Size& size, float scale_factor) override;
   void BindFramebuffer() override;
   void SwapBuffers(cc::CompositorFrame* frame) override;
 
  private:
   // CompositorOutputSurface overrides.
   void OnSwapAck(uint32 output_surface_id,
                  const cc::CompositorFrameAck& ack) override;
@@ skipping 19 matching lines @@
   std::queue<TransferableFrame> returned_textures_;
 
   uint32 fbo_;
   bool is_backbuffer_discarded_;
   cc::ResourceFormat format_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_MAILBOX_OUTPUT_SURFACE_H_