Index: ui/compositor/compositor_vsync_manager.h |
diff --git a/ui/compositor/compositor_vsync_manager.h b/ui/compositor/compositor_vsync_manager.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..7e9e07b862653ee3de01c6bbd94dd958246c9fa5 |
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+++ b/ui/compositor/compositor_vsync_manager.h |
@@ -0,0 +1,65 @@ |
+// 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_ |