Tighter sync and faster ACK on SwapBuffers/PostSubBuffers

ui/aura/bench/bench_main.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 "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/i18n/icu_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
@@ skipping 71 matching lines @@
 // Benchmark base class, hooks up drawing callback and displaying FPS.
 class BenchCompositorObserver : public ui::CompositorObserver {
  public:
   explicit BenchCompositorObserver(int max_frames)
       : start_time_(),
         frames_(0),
         max_frames_(max_frames) {
   }
   virtual void OnCompositingStarted(Compositor* compositor) OVERRIDE {}
 
+  virtual void OnCompositingWillEnd(Compositor* compositor) OVERRIDE {}
+
   virtual void OnCompositingEnded(Compositor* compositor) OVERRIDE {
     if (start_time_.is_null()) {
       start_time_ = TimeTicks::Now();
     } else {
       ++frames_;
       if (frames_ % kFrames == 0) {
         TimeTicks now = TimeTicks::Now();
         double ms = (now - start_time_).InMillisecondsF() / kFrames;
         LOG(INFO) << "FPS: " << 1000.f / ms << " (" << ms << " ms)";
         start_time_ = now;
@@ skipping 221 matching lines @@
 #endif
 
   root_window->ShowRootWindow();
   MessageLoopForUI::current()->Run();
   root_window.reset();
 
   ui::CompositorTestSupport::Terminate();
 
   return 0;
 }