CrOS: Look for consistency between successive vsync intervals.

ui/gl/vsync_provider.h

 // Copyright (c) 2013 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.
 
 #ifndef UI_GL_VSYNC_PROVIDER_H_
 #define UI_GL_VSYNC_PROVIDER_H_
 
+#include <queue>
+
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/time.h"
 
 namespace gfx {
 
 class VSyncProvider {
  public:
   VSyncProvider();
   virtual ~VSyncProvider();
@@ skipping 29 matching lines @@
                              int64* media_stream_counter,
                              int64* swap_buffer_counter) = 0;
 
   virtual bool GetMscRate(int32* numerator, int32* denominator) = 0;
 
  private:
   base::TimeTicks last_timebase_;
   uint64 last_media_stream_counter_;
   base::TimeDelta last_good_interval_;
 
+  // A short history of the last few computed intervals.
+  // We use this to filter out the noise in the computation resulting
+  // from configuration change (monitor reconfiguration, moving windows
+  // between monitors, suspend and resume, etc.).
+  std::queue<base::TimeDelta> last_computed_intervals_;
+
   DISALLOW_COPY_AND_ASSIGN(SyncControlVSyncProvider);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_VSYNC_PROVIDER_H_