gpu: Remove Echo and SwapCompletion GL interfacess

mojo/gles2/command_buffer_client_impl.cc

 // 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.
 
 #include "mojo/gles2/command_buffer_client_impl.h"
 
 #include <limits>
 
 #include "base/logging.h"
 #include "base/process/process_handle.h"
@@ skipping 223 matching lines @@
                                           const base::Closure& callback) {
   // TODO(piman)
   NOTIMPLEMENTED();
 }
 
 void CommandBufferClientImpl::SetSurfaceVisible(bool visible) {
   // TODO(piman)
   NOTIMPLEMENTED();
 }
 
-void CommandBufferClientImpl::Echo(const base::Closure& callback) {
-  command_buffer_->Echo(callback);
-}
-
 uint32 CommandBufferClientImpl::CreateStreamTexture(uint32 texture_id) {
   // TODO(piman)
   NOTIMPLEMENTED();
   return 0;
 }
 
 void CommandBufferClientImpl::DidDestroy() {
   LostContext(gpu::error::kUnknown);
 }
 
@@ skipping 23 matching lines @@
     DidDestroy();
     return;
   }
 
   if (state->generation - last_state_.generation < 0x80000000U)
     last_state_ = state.To<State>();
 }
 
 }  // namespace gles2
 }  // namespace mojo