Remove parts of //cc we aren't using

cc/layers/scrollbar_layer_interface.h

-// Copyright 2013 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 CC_LAYERS_SCROLLBAR_LAYER_INTERFACE_H_
-#define CC_LAYERS_SCROLLBAR_LAYER_INTERFACE_H_
-
-#include "cc/base/cc_export.h"
-#include "cc/input/scrollbar.h"
-
-namespace cc {
-
-class Layer;
-class LayerImpl;
-
-class CC_EXPORT ScrollbarLayerInterface {
- public:
-  virtual int ScrollLayerId() const = 0;
-  virtual void SetScrollLayer(int layer_id) = 0;
-  virtual void SetClipLayer(int layer_id) = 0;
-  virtual void PushScrollClipPropertiesTo(LayerImpl* layer) = 0;
-
-  virtual ScrollbarOrientation orientation() const = 0;
-
- protected:
-  ScrollbarLayerInterface() {}
-  virtual ~ScrollbarLayerInterface() {}
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ScrollbarLayerInterface);
-};
-
-}  // namespace cc
-
-#endif  // CC_LAYERS_SCROLLBAR_LAYER_INTERFACE_H_