It is time.

ui/compositor/compositor_animation_observer.h

Index: ui/compositor/compositor_animation_observer.h
diff --git a/ui/compositor/compositor_animation_observer.h b/ui/compositor/compositor_animation_observer.h
deleted file mode 100644
index facfe5a04824efd37a57bb3d6595a6cf7b3e560c..0000000000000000000000000000000000000000
--- a/ui/compositor/compositor_animation_observer.h
+++ /dev/null
@@ -1,22 +0,0 @@
-// 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_ANIMATION_OBSERVER_H_
-#define UI_COMPOSITOR_COMPOSITOR_ANIMATION_OBSERVER_H_
-
-#include "base/time/time.h"
-#include "ui/compositor/compositor_export.h"
-
-namespace ui {
-
-class COMPOSITOR_EXPORT CompositorAnimationObserver {
- public:
-  virtual ~CompositorAnimationObserver() {}
-
-  virtual void OnAnimationStep(base::TimeTicks timestamp) = 0;
-};
-
-}  // namespace ui
-
-#endif  // UI_COMPOSITOR_COMPOSITOR_ANIMATION_OBSERVER_H_