Rework FlushSync to return early if commands have been processed since the last update

gpu/ipc/gpu_command_buffer_traits.cc

 // Copyright (c) 2011 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 "gpu/ipc/gpu_command_buffer_traits.h"
 
 namespace IPC {
 
 void ParamTraits<gpu::CommandBuffer::State> ::Write(Message* m,
                                                     const param_type& p) {
   WriteParam(m, p.num_entries);
   WriteParam(m, p.get_offset);
   WriteParam(m, p.put_offset);
   WriteParam(m, p.token);
   WriteParam(m, static_cast<int32>(p.error));
+  WriteParam(m, p.generation);
 }
 
 bool ParamTraits<gpu::CommandBuffer::State> ::Read(const Message* m,
                                                    void** iter,
                                                    param_type* p) {
   int32 temp;
   if (ReadParam(m, iter, &p->num_entries) &&
       ReadParam(m, iter, &p->get_offset) &&
       ReadParam(m, iter, &p->put_offset) &&
       ReadParam(m, iter, &p->token) &&
-      ReadParam(m, iter, &temp)) {
+      ReadParam(m, iter, &temp) &&
+      ReadParam(m, iter, &p->generation)) {
     p->error = static_cast<gpu::error::Error>(temp);
     return true;
   } else {
     return false;
   }
 }
 
 void ParamTraits<gpu::CommandBuffer::State> ::Log(const param_type& p,
                                                   std::string* l) {
   l->append("<CommandBuffer::State>");
 }
 
 }  // namespace IPC