cc: Implement unified BeginFrame on aura

ui/compositor/compositor_vsync_manager.h

-// 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.
-
-#ifndef UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_
-#define UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_
-
-#include "base/memory/ref_counted.h"
-#include "base/observer_list.h"
-#include "base/synchronization/lock.h"
-#include "base/time/time.h"
-#include "ui/compositor/compositor_export.h"
-
-namespace ui {
-
-// This class manages vsync parameters for a compositor. It merges updates of
-// the parameters from different sources and sends the merged updates to
-// observers which register to it.
-class COMPOSITOR_EXPORT CompositorVSyncManager
-    : public base::RefCounted<CompositorVSyncManager> {
- public:
-  class Observer {
-   public:
-    virtual void OnUpdateVSyncParameters(base::TimeTicks timebase,
-                                         base::TimeDelta interval) = 0;
-  };
-
-  CompositorVSyncManager();
-
-  // The "authoritative" vsync interval, if provided, will override |interval|
-  // as reported by UpdateVSyncParameters() whenever it is called.  This is
-  // typically the value reported by a more reliable source, e.g. the platform
-  // display configuration.  In the particular case of ChromeOS -- this is the
-  // value queried through XRandR, which is more reliable than the value
-  // queried through the 3D context.
-  void SetAuthoritativeVSyncInterval(base::TimeDelta interval);
-
-  // The vsync parameters consist of |timebase|, which is the platform timestamp
-  // of the last vsync, and |interval|, which is the interval between vsyncs.
-  // |interval| may be overriden by SetAuthoritativeVSyncInterval() above.
-  void UpdateVSyncParameters(base::TimeTicks timebase,
-                             base::TimeDelta interval);
-
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
- private:
-  friend class base::RefCounted<CompositorVSyncManager>;
-
-  ~CompositorVSyncManager();
-
-  void NotifyObservers(base::TimeTicks timebase, base::TimeDelta interval);
-
-  ObserverList<Observer> observer_list_;
-
-  base::TimeTicks last_timebase_;
-  base::TimeDelta last_interval_;
-  base::TimeDelta authoritative_vsync_interval_;
-
-  DISALLOW_COPY_AND_ASSIGN(CompositorVSyncManager);
-};
-
-}  // namespace ui
-
-#endif  // UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_