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

cc/layers/scrollbar_layer.cc

Index: cc/layers/scrollbar_layer.cc
diff --git a/cc/layers/scrollbar_layer.cc b/cc/layers/scrollbar_layer.cc
index a2fdd58ee36ac859f388cff2325df445a56b432f..d999ddce4b678e443d72203d8f8ae849df9ec881 100644
--- a/cc/layers/scrollbar_layer.cc
+++ b/cc/layers/scrollbar_layer.cc
@@ -36,8 +36,8 @@ scoped_refptr<ScrollbarLayer> ScrollbarLayer::Create(
 ScrollbarLayer::ScrollbarLayer(
     scoped_ptr<Scrollbar> scrollbar,
     int scroll_layer_id)
-    : scrollbar_(scrollbar.Pass()),
-      scroll_layer_id_(scroll_layer_id) {
+    : scroll_layer_id_(scroll_layer_id),
+      scrollbar_(scrollbar.Pass()) {
   if (!scrollbar_->IsOverlay())
     SetShouldScrollOnMainThread(true);
 }
@@ -56,8 +56,8 @@ bool ScrollbarLayer::OpacityCanAnimateOnImplThread() const {
   return scrollbar_->IsOverlay();
 }
 
-ScrollbarOrientation ScrollbarLayer::Orientation() const {
-  return scrollbar_->Orientation();
+ScrollbarLayerInterface* ScrollbarLayer::ToScrollbarLayer() {
+  return this;
 }
 
 int ScrollbarLayer::MaxTextureSize() {
@@ -65,10 +65,15 @@ int ScrollbarLayer::MaxTextureSize() {
   return layer_tree_host()->GetRendererCapabilities().max_texture_size;
 }
 
-float ScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
-  if (layer_tree_host()->settings().solid_color_scrollbars)
-    return scale;
+int ScrollbarLayer::ScrollLayerId() const {
+  return scroll_layer_id_;
+}
+
+ScrollbarOrientation ScrollbarLayer::orientation() const {
+  return scrollbar_->Orientation();
+}
 
+float ScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
   // If the scaled content_bounds() is bigger than the max texture size of the
   // device, we need to clamp it by rescaling, since content_bounds() is used
   // below to set the texture size.
@@ -105,23 +110,9 @@ void ScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
 
   ScrollbarLayerImpl* scrollbar_layer = static_cast<ScrollbarLayerImpl*>(layer);
 
-  if (layer_tree_host() &&
-      layer_tree_host()->settings().solid_color_scrollbars) {
-    int thickness_override =
-        layer_tree_host()->settings().solid_color_scrollbar_thickness_dip;
-    if (thickness_override != -1) {
-      scrollbar_layer->SetThumbThickness(thickness_override);
-    } else {
-      if (Orientation() == HORIZONTAL)
-        scrollbar_layer->SetThumbThickness(bounds().height());
-      else
-        scrollbar_layer->SetThumbThickness(bounds().width());
-    }
-  } else {
-    scrollbar_layer->SetThumbThickness(thumb_thickness_);
-  }
+  scrollbar_layer->SetThumbThickness(thumb_thickness_);
   scrollbar_layer->SetThumbLength(thumb_length_);
-  if (Orientation() == HORIZONTAL) {
+  if (orientation() == HORIZONTAL) {
     scrollbar_layer->SetTrackStart(track_rect_.x());
     scrollbar_layer->SetTrackLength(track_rect_.width());
   } else {
@@ -140,10 +131,6 @@ void ScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
   needs_push_properties_ = true;
 }
 
-ScrollbarLayer* ScrollbarLayer::ToScrollbarLayer() {
-  return this;
-}
-
 void ScrollbarLayer::SetLayerTreeHost(LayerTreeHost* host) {
   // When the LTH is set to null or has changed, then this layer should remove
   // all of its associated resources.
@@ -170,7 +157,7 @@ gfx::Rect ScrollbarLayer::ScrollbarLayerRectToContentRect(
 
 gfx::Rect ScrollbarLayer::OriginThumbRect() const {
   gfx::Size thumb_size;
-  if (Orientation() == HORIZONTAL) {
+  if (orientation() == HORIZONTAL) {
     thumb_size =
         gfx::Size(scrollbar_->ThumbLength(), scrollbar_->ThumbThickness());
   } else {
@@ -186,8 +173,7 @@ bool ScrollbarLayer::Update(ResourceUpdateQueue* queue,
   gfx::Rect scaled_track_rect = ScrollbarLayerRectToContentRect(
       gfx::Rect(scrollbar_->Location(), bounds()));
 
-  if (layer_tree_host()->settings().solid_color_scrollbars ||
-      track_rect_.IsEmpty() || scaled_track_rect.IsEmpty())
+  if (track_rect_.IsEmpty() || scaled_track_rect.IsEmpty())
     return false;
 
   {
@@ -213,7 +199,6 @@ bool ScrollbarLayer::Update(ResourceUpdateQueue* queue,
 scoped_refptr<UIResourceBitmap> ScrollbarLayer::RasterizeScrollbarPart(
     gfx::Rect rect,
     ScrollbarPart part) {
-  DCHECK(!layer_tree_host()->settings().solid_color_scrollbars);
   DCHECK(!rect.size().IsEmpty());
 
   scoped_refptr<UIResourceBitmap> bitmap =