Refactor cc scrollbar layers to separate solid-color vs desktop.

cc/layers/layer.h

 // Copyright 2010 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_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 26 matching lines @@
 struct AnimationEvent;
 class CopyOutputRequest;
 class LayerAnimationDelegate;
 class LayerAnimationEventObserver;
 class LayerImpl;
 class LayerTreeHost;
 class LayerTreeImpl;
 class PriorityCalculator;
 class RenderingStatsInstrumentation;
 class ResourceUpdateQueue;
-class ScrollbarLayer;
+class ScrollbarLayerBase;
 struct AnimationEvent;
 
 // Base class for composited layers. Special layer types are derived from
 // this class.
 class CC_EXPORT Layer : public base::RefCounted<Layer>,
                         public LayerAnimationValueObserver {
  public:
   enum LayerIdLabels {
     INVALID_ID = -1,
   };
@@ skipping 276 matching lines @@
 
   bool HasActiveAnimation() const;
 
   void AddLayerAnimationEventObserver(
       LayerAnimationEventObserver* animation_observer);
   void RemoveLayerAnimationEventObserver(
       LayerAnimationEventObserver* animation_observer);
 
   virtual Region VisibleContentOpaqueRegion() const;
 
-  virtual ScrollbarLayer* ToScrollbarLayer();
+  virtual ScrollbarLayerBase* ToScrollbarLayerBase();
 
   gfx::Rect LayerRectToContentRect(const gfx::RectF& layer_rect) const;
 
   // In impl-side painting, this returns true if this layer type is not
   // compatible with the main thread running freely, such as a double-buffered
   // canvas that doesn't want to be triple-buffered across all three trees.
   virtual bool BlocksPendingCommit() const;
   // Returns true if anything in this tree blocksPendingCommit.
   bool BlocksPendingCommitRecursive() const;
 
@@ skipping 132 matching lines @@
   DrawProperties<Layer, RenderSurface> draw_properties_;
 
   PaintProperties paint_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_