cc: Remove unused proto conversion code.

cc/layers/solid_color_scrollbar_layer.h

Index: cc/layers/solid_color_scrollbar_layer.h
diff --git a/cc/layers/solid_color_scrollbar_layer.h b/cc/layers/solid_color_scrollbar_layer.h
index 2a11453b28a286819255a70b133d15bc9142e09c..2d90f116fc122743120d1f285609474e755c6d4d 100644
--- a/cc/layers/solid_color_scrollbar_layer.h
+++ b/cc/layers/solid_color_scrollbar_layer.h
@@ -29,9 +29,6 @@ class CC_EXPORT SolidColorScrollbarLayer : public ScrollbarLayerInterface,
   bool AlwaysUseActiveTreeOpacity() const override;
   ScrollbarLayerInterface* ToScrollbarLayer() override;
   void ToLayerNodeProto(proto::LayerNode* proto) const override;
-  void FromLayerNodeProto(const proto::LayerNode& proto,
-                          const LayerIdMap& layer_map,
-                          LayerTreeHost* layer_tree_host) override;
 
   void SetOpacity(float opacity) override;
   void PushPropertiesTo(LayerImpl* layer) override;
@@ -44,6 +41,18 @@ class CC_EXPORT SolidColorScrollbarLayer : public ScrollbarLayerInterface,
 
   ScrollbarOrientation orientation() const override;
 
+  int thumb_thickness() const {
+    return solid_color_scrollbar_layer_inputs_.thumb_thickness;
+  }
+
+  int track_start() const {
+    return solid_color_scrollbar_layer_inputs_.track_start;
+  }
+
+  bool is_left_side_vertical_scrollbar() const {
+    return solid_color_scrollbar_layer_inputs_.is_left_side_vertical_scrollbar;
+  }
+
  protected:
   SolidColorScrollbarLayer(ScrollbarOrientation orientation,
                            int thumb_thickness,