Implement Discard and EnsureBackbufferCHROMIUM using command buffer instead of IPC.

content/common/gpu/client/command_buffer_proxy_impl.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/common/gpu/client/command_buffer_proxy_impl.h"
 
 #include "base/callback.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/process_util.h"
@@ skipping 358 matching lines @@
   return true;
 }
 
 bool CommandBufferProxyImpl::SetSurfaceVisible(bool visible) {
   if (last_state_.error != gpu::error::kNoError)
     return false;
 
   return Send(new GpuCommandBufferMsg_SetSurfaceVisible(route_id_, visible));
 }
 
-bool CommandBufferProxyImpl::DiscardBackbuffer() {
-  if (last_state_.error != gpu::error::kNoError)
-    return false;
-
-  return Send(new GpuCommandBufferMsg_DiscardBackbuffer(route_id_));
-}
-
-bool CommandBufferProxyImpl::EnsureBackbuffer() {
-  if (last_state_.error != gpu::error::kNoError)
-    return false;
-
-  return Send(new GpuCommandBufferMsg_EnsureBackbuffer(route_id_));
-}
-
 bool CommandBufferProxyImpl::SetParent(
     CommandBufferProxy* parent_command_buffer,
     uint32 parent_texture_id) {
   if (last_state_.error != gpu::error::kNoError)
     return false;
 
   bool result;
   if (parent_command_buffer) {
     if (!Send(new GpuCommandBufferMsg_SetParent(
         route_id_,
@@ skipping 77 matching lines @@
 
 void CommandBufferProxyImpl::SetOnConsoleMessageCallback(
     const GpuConsoleMessageCallback& callback) {
   console_message_callback_ = callback;
 }
 
 void CommandBufferProxyImpl::TryUpdateState() {
   if (last_state_.error == gpu::error::kNoError)
     shared_state_->Read(&last_state_);
 }