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

cc/layers/scrollbar_layer.h

Index: cc/layers/scrollbar_layer.h
diff --git a/cc/layers/scrollbar_layer.h b/cc/layers/scrollbar_layer.h
index f500dcc66d277dd8d46e0e835239fb844e367a5f..663b3d69d276b7495f75cedde44080b67562da29 100644
--- a/cc/layers/scrollbar_layer.h
+++ b/cc/layers/scrollbar_layer.h
@@ -8,6 +8,7 @@
 #include "cc/base/cc_export.h"
 #include "cc/input/scrollbar.h"
 #include "cc/layers/contents_scaling_layer.h"
+#include "cc/layers/scrollbar_layer_interface.h"
 #include "cc/layers/scrollbar_theme_painter.h"
 #include "cc/resources/layer_updater.h"
 
@@ -16,7 +17,8 @@ class CachingBitmapContentLayerUpdater;
 class ResourceUpdateQueue;
 class ScrollbarThemeComposite;
 
-class CC_EXPORT ScrollbarLayer : public ContentsScalingLayer {
+class CC_EXPORT ScrollbarLayer : public ScrollbarLayerInterface,

[aelias_OOO_until_Jul13, 2013/08/14 21:26:08]

This name sounds like it's a base class of all scrollbars.  How about renaming
it to PaintedScrollbarLayer?

[wjmaclean, 2013/08/15 20:09:40]

I agree.

Since that's going to touch a lot of files, and this CL is already getting
pretty big, can we do that in a follow-on CL?

[aelias_OOO_until_Jul13, 2013/08/15 21:22:32]

It's fine with me to delay the change.

+                                 public ContentsScalingLayer {
  public:
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE;
@@ -25,12 +27,14 @@ class CC_EXPORT ScrollbarLayer : public ContentsScalingLayer {
       scoped_ptr<Scrollbar> scrollbar,
       int scroll_layer_id);
 
-  int scroll_layer_id() const { return scroll_layer_id_; }
-  void SetScrollLayerId(int id);
-
   virtual bool OpacityCanAnimateOnImplThread() const OVERRIDE;
+  virtual ScrollbarLayerInterface* ToScrollbarLayer() OVERRIDE;
+
+  // ScrollbarLayerInterface
+  virtual int scroll_layer_id() const OVERRIDE;

[enne (OOO), 2013/08/14 21:01:09]

style nit: don't use hacker_style for virtual functions.  Here and elsewhere.

[wjmaclean, 2013/08/15 20:09:40]

Done.

+  virtual void SetScrollLayerId(int id) OVERRIDE;
 
-  ScrollbarOrientation Orientation() const;
+  virtual ScrollbarOrientation orientation() const OVERRIDE;
 
   // Layer interface
   virtual void SetTexturePriorities(const PriorityCalculator& priority_calc)
@@ -47,8 +51,6 @@ class CC_EXPORT ScrollbarLayer : public ContentsScalingLayer {
                                       float* contents_scale_y,
                                       gfx::Size* content_bounds) OVERRIDE;
 
-  virtual ScrollbarLayer* ToScrollbarLayer() OVERRIDE;
-
  protected:
   ScrollbarLayer(scoped_ptr<Scrollbar> scrollbar,
                  int scroll_layer_id);
@@ -68,12 +70,14 @@ class CC_EXPORT ScrollbarLayer : public ContentsScalingLayer {
   int MaxTextureSize();
   float ClampScaleToMaxTextureSize(float scale);
 
+  int scroll_layer_id_;
+  ScrollbarOrientation orientation_;
+
   scoped_ptr<Scrollbar> scrollbar_;
 
   int thumb_thickness_;
   int thumb_length_;
   gfx::Rect track_rect_;
-  int scroll_layer_id_;
 
   unsigned texture_format_;