cc: Make PaintedScrollbarLayer not use ContentsScalingLayer

cc/layers/painted_scrollbar_layer_impl.cc

Index: cc/layers/painted_scrollbar_layer_impl.cc
diff --git a/cc/layers/painted_scrollbar_layer_impl.cc b/cc/layers/painted_scrollbar_layer_impl.cc
index 068d42f2a5f626b255cb5c9c5b058a41f68bc64c..6c830355c0610cc255049d7898ba36eca929bcd1 100644
--- a/cc/layers/painted_scrollbar_layer_impl.cc
+++ b/cc/layers/painted_scrollbar_layer_impl.cc
@@ -32,6 +32,7 @@ PaintedScrollbarLayerImpl::PaintedScrollbarLayerImpl(
     : ScrollbarLayerImplBase(tree_impl, id, orientation, false, false),
       track_ui_resource_id_(0),
       thumb_ui_resource_id_(0),
+      internal_content_scale_(1.f),
       thumb_thickness_(0),
       thumb_length_(0),
       track_start_(0),
@@ -51,6 +52,9 @@ void PaintedScrollbarLayerImpl::PushPropertiesTo(LayerImpl* layer) {
   PaintedScrollbarLayerImpl* scrollbar_layer =
       static_cast<PaintedScrollbarLayerImpl*>(layer);
 
+  scrollbar_layer->set_internal_content_scale_and_bounds(
+      internal_content_scale_, internal_content_bounds_);
+
   scrollbar_layer->SetThumbThickness(thumb_thickness_);
   scrollbar_layer->SetThumbLength(thumb_length_);
   scrollbar_layer->SetTrackStart(track_start_);
@@ -76,14 +80,14 @@ void PaintedScrollbarLayerImpl::AppendQuads(
   gfx::PointF uv_top_left(0.f, 0.f);
   gfx::PointF uv_bottom_right(1.f, 1.f);
   gfx::Rect bounds_rect(bounds());
-  gfx::Rect content_bounds_rect(content_bounds());
+  gfx::Rect content_bounds_rect(internal_content_bounds_);
 
   SharedQuadState* shared_quad_state =
       render_pass->CreateAndAppendSharedQuadState();
-  PopulateSharedQuadState(shared_quad_state);
+  PopulateScaledSharedQuadState(shared_quad_state, internal_content_scale_);
 
-  AppendDebugBorderQuad(
-      render_pass, content_bounds(), shared_quad_state, append_quads_data);
+  AppendDebugBorderQuad(render_pass, internal_content_bounds_,
+                        shared_quad_state, append_quads_data);
 
   gfx::Rect thumb_quad_rect = ComputeThumbQuadRect();
   gfx::Rect visible_thumb_quad_rect =