Revert of cc: Implement shared worker contexts.

content/renderer/gpu/mailbox_output_surface.cc

 // 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.
 
 #include "content/renderer/gpu/mailbox_output_surface.h"
 
 #include "base/logging.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/compositor_frame_ack.h"
 #include "cc/output/gl_frame_data.h"
@@ skipping 27 matching lines @@
                               swap_frame_message_queue,
                               true),
       fbo_(0),
       is_backbuffer_discarded_(false),
       format_(format) {
   pending_textures_.push_back(TransferableFrame());
   capabilities_.uses_default_gl_framebuffer = false;
 }
 
 MailboxOutputSurface::~MailboxOutputSurface() {
-}
-
-void MailboxOutputSurface::DetachFromClient() {
   DiscardBackbuffer();
   while (!pending_textures_.empty()) {
     if (pending_textures_.front().texture_id) {
       context_provider_->ContextGL()->DeleteTextures(
           1, &pending_textures_.front().texture_id);
     }
     pending_textures_.pop_front();
   }
-  cc::OutputSurface::DetachFromClient();
 }
 
 void MailboxOutputSurface::EnsureBackbuffer() {
   is_backbuffer_discarded_ = false;
 
   GLES2Interface* gl = context_provider_->ContextGL();
 
   if (!current_backing_.texture_id) {
     // Find a texture of matching size to recycle.
     while (!returned_textures_.empty()) {
@@ skipping 145 matching lines @@
   pending_textures_.push_back(current_backing_);
   current_backing_ = TransferableFrame();
 }
 
 size_t MailboxOutputSurface::GetNumAcksPending() {
   DCHECK(pending_textures_.size());
   return pending_textures_.size() - 1;
 }
 
 }  // namespace content