It is time.

ui/compositor/compositor_observer.h

-// 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.
-
-#ifndef UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
-#define UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
-
-#include "base/time/time.h"
-#include "ui/compositor/compositor_export.h"
-
-namespace ui {
-
-class Compositor;
-
-// A compositor observer is notified when compositing completes.
-class COMPOSITOR_EXPORT CompositorObserver {
- public:
-  CompositorObserver();
-
-  // A commit proxies information from the main thread to the compositor
-  // thread. It typically happens when some state changes that will require a
-  // composite. In the multi-threaded case, many commits may happen between
-  // two successive composites. In the single-threaded, a single commit
-  // between two composites (just before the composite as part of the
-  // composite cycle). If the compositor is locked, it will not send this
-  // this signal.
-  virtual void OnCompositingDidCommit(Compositor* compositor) = 0;
-
-  // Called when compositing started: it has taken all the layer changes into
-  // account and has issued the graphics commands.
-  virtual void OnCompositingStarted(Compositor* compositor,
-                                    base::TimeTicks start_time) = 0;
-
-  // Called when compositing completes: the present to screen has completed.
-  virtual void OnCompositingEnded(Compositor* compositor) = 0;
-
-  // Called when compositing is aborted (e.g. lost graphics context).
-  virtual void OnCompositingAborted(Compositor* compositor) = 0;
-
-  // Called when the compositor lock state changes.
-  virtual void OnCompositingLockStateChanged(Compositor* compositor) = 0;
-
- protected:
-#if defined(OS_MACOSX)
-  // Debugging instrumentation for crbug.com/401630.
-  // TODO(ccameron): remove this.
-  friend class Compositor;
-  int32 observing_count_;
-#endif
-
-  virtual ~CompositorObserver();
-};
-
-}  // namespace ui
-
-#endif  // UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_