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// 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/macros.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 ~Observer() = default;
virtual void OnUpdateVSyncParameters(base::TimeTicks timebase,
base::TimeDelta interval) = 0;
};
CompositorVSyncManager();
// The vsync parameters consist of |timebase|, which is the platform timestamp
// of the last vsync, and |interval|, which is the interval between vsyncs.
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);
base::ObserverList<Observer>::Unchecked observer_list_;
base::TimeTicks last_timebase_;
base::TimeDelta last_interval_;
DISALLOW_COPY_AND_ASSIGN(CompositorVSyncManager);
};
} // namespace ui
#endif // UI_COMPOSITOR_COMPOSITOR_VSYNC_MANAGER_H_