Implemented screen rotation animation experiment.

ash/rotator/screen_rotation_animator.h

Index: ash/rotator/screen_rotation_animator.h
diff --git a/ash/rotator/screen_rotation_animator.h b/ash/rotator/screen_rotation_animator.h
new file mode 100644
index 0000000000000000000000000000000000000000..055e755906dc483d95f4da29cc666749d893eb66
--- /dev/null
+++ b/ash/rotator/screen_rotation_animator.h
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+// Copyright 2015 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 ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_
+#define ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_
+
+#include "ash/ash_export.h"
+#include "base/basictypes.h"
+#include "ui/gfx/display.h"
+
+namespace ash {
+
+// Utility to perform a screen rotation with an animation.
+class ASH_EXPORT ScreenRotationAnimator {
+ public:
+  explicit ScreenRotationAnimator(int64 display_id);
+  ~ScreenRotationAnimator();
+
+  // Rotates |display_| to the |new_rotation| orientation.
+  void Rotate(gfx::Display::Rotation new_rotation);
+
+ private:
+  // The id of the display to rotate.
+  int64 display_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreenRotationAnimator);
+};
+
+}  // namespace ash
+
+#endif  // ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_