gpu: Remove Echo and SwapCompletion GL interfacess

ppapi/proxy/ppapi_command_buffer_proxy.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 "ppapi/proxy/ppapi_command_buffer_proxy.h"
 
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/proxy_channel.h"
 #include "ppapi/shared_impl/api_id.h"
 #include "ppapi/shared_impl/host_resource.h"
@@ skipping 127 matching lines @@
 }
 
 void PpapiCommandBufferProxy::DestroyTransferBuffer(int32 id) {
   if (last_state_.error != gpu::error::kNoError)
     return;
 
   Send(new PpapiHostMsg_PPBGraphics3D_DestroyTransferBuffer(
       ppapi::API_ID_PPB_GRAPHICS_3D, resource_, id));
 }
 
-void PpapiCommandBufferProxy::Echo(const base::Closure& callback) {
-  NOTREACHED();
-}
-
 uint32 PpapiCommandBufferProxy::CreateStreamTexture(uint32 texture_id) {
   NOTREACHED();
   return 0;
 }
 
 uint32 PpapiCommandBufferProxy::InsertSyncPoint() {
   uint32 sync_point = 0;
   if (last_state_.error == gpu::error::kNoError) {
     Send(new PpapiHostMsg_PPBGraphics3D_InsertSyncPoint(
          ppapi::API_ID_PPB_GRAPHICS_3D, resource_, &sync_point));
@@ skipping 81 matching lines @@
     shared_state()->Read(&last_state_);
 }
 
 gpu::CommandBufferSharedState* PpapiCommandBufferProxy::shared_state() const {
   return reinterpret_cast<gpu::CommandBufferSharedState*>(
       shared_state_shm_->memory());
 }
 
 }  // namespace proxy
 }  // namespace ppapi