cc: Cleanup class/struct forward declarations

cc/layers/painted_scrollbar_layer_impl.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_PAINTED_SCROLLBAR_LAYER_IMPL_H_
 #define CC_LAYERS_PAINTED_SCROLLBAR_LAYER_IMPL_H_
 
 #include "base/macros.h"
 #include "cc/base/cc_export.h"
 #include "cc/input/scrollbar.h"
 #include "cc/layers/scrollbar_layer_impl_base.h"
 #include "cc/resources/ui_resource_client.h"
 
 namespace cc {
 
 class LayerTreeImpl;
-class ScrollView;
 
 class CC_EXPORT PaintedScrollbarLayerImpl : public ScrollbarLayerImplBase {
  public:
   static std::unique_ptr<PaintedScrollbarLayerImpl> Create(
       LayerTreeImpl* tree_impl,
       int id,
       ScrollbarOrientation orientation,
       bool is_left_side_vertical_scrollbar,
       bool is_overlay);
   ~PaintedScrollbarLayerImpl() override;
@@ skipping 56 matching lines @@
   int thumb_thickness_;
   int thumb_length_;
   int track_start_;
   int track_length_;
 
   DISALLOW_COPY_AND_ASSIGN(PaintedScrollbarLayerImpl);
 };
 
 }  // namespace cc
 #endif  // CC_LAYERS_PAINTED_SCROLLBAR_LAYER_IMPL_H_