Pinch/Zoom Infrastructure & Plumbing CL

cc/layers/painted_scrollbar_layer.cc

Index: cc/layers/painted_scrollbar_layer.cc
diff --git a/cc/layers/painted_scrollbar_layer.cc b/cc/layers/painted_scrollbar_layer.cc
index 4466d58a3de7ac579aeb084aa4cd89287b5c7745..ceee25e677926b220cde7a1db983d32117516db3 100644
--- a/cc/layers/painted_scrollbar_layer.cc
+++ b/cc/layers/painted_scrollbar_layer.cc
@@ -38,6 +38,7 @@ PaintedScrollbarLayer::PaintedScrollbarLayer(
     int scroll_layer_id)
     : scrollbar_(scrollbar.Pass()),
       scroll_layer_id_(scroll_layer_id),
+      clip_layer_id_(Layer::INVALID_ID),
       thumb_thickness_(scrollbar_->ThumbThickness()),
       thumb_length_(scrollbar_->ThumbLength()),
       is_overlay_(scrollbar_->IsOverlay()),
@@ -52,11 +53,19 @@ int PaintedScrollbarLayer::ScrollLayerId() const {
   return scroll_layer_id_;
 }
 
-void PaintedScrollbarLayer::SetScrollLayerId(int id) {
-  if (id == scroll_layer_id_)
+void PaintedScrollbarLayer::SetScrollLayer(int layer_id) {
+  if (layer_id == scroll_layer_id_)
     return;
 
-  scroll_layer_id_ = id;
+  scroll_layer_id_ = layer_id;
+  SetNeedsFullTreeSync();
+}
+
+void PaintedScrollbarLayer::SetClipLayer(int layer_id) {
+  if (layer_id == clip_layer_id_)
+    return;
+
+  clip_layer_id_ = layer_id;
   SetNeedsFullTreeSync();
 }
 
@@ -109,6 +118,8 @@ void PaintedScrollbarLayer::CalculateContentsScale(
 void PaintedScrollbarLayer::PushPropertiesTo(LayerImpl* layer) {
   ContentsScalingLayer::PushPropertiesTo(layer);
 
+  PushScrollClipPropertiesTo(layer);
+
   PaintedScrollbarLayerImpl* scrollbar_layer =
       static_cast<PaintedScrollbarLayerImpl*>(layer);
 
@@ -136,6 +147,14 @@ ScrollbarLayerInterface* PaintedScrollbarLayer::ToScrollbarLayer() {
   return this;
 }
 
+void PaintedScrollbarLayer::PushScrollClipPropertiesTo(LayerImpl* layer) {
+  PaintedScrollbarLayerImpl* scrollbar_layer =
+      static_cast<PaintedScrollbarLayerImpl*>(layer);
+
+  scrollbar_layer->SetScrollLayerById(scroll_layer_id_);
+  scrollbar_layer->SetClipLayerById(clip_layer_id_);
+}
+
 void PaintedScrollbarLayer::SetLayerTreeHost(LayerTreeHost* host) {
   // When the LTH is set to null or has changed, then this layer should remove
   // all of its associated resources.