Implement CSS: scroll-boundary-behavior

cc/trees/property_tree_builder.cc

Index: cc/trees/property_tree_builder.cc
diff --git a/cc/trees/property_tree_builder.cc b/cc/trees/property_tree_builder.cc
index edba9991951d3473ac5ee3fb00b0f2e9058e29c4..e7755291c6884327848f95c9b7218592efe03a3d 100644
--- a/cc/trees/property_tree_builder.cc
+++ b/cc/trees/property_tree_builder.cc
@@ -989,6 +989,15 @@ static inline bool UserScrollableVertical(LayerImpl* layer) {
   return layer->test_properties()->user_scrollable_vertical;
 }
 
+static inline ScrollBoundaryBehavior GetScrollBoundaryBehavior(Layer* layer) {
+  return layer->scroll_boundary_behavior();
+}
+
+static inline ScrollBoundaryBehavior GetScrollBoundaryBehavior(
+    LayerImpl* layer) {
+  return layer->test_properties()->scroll_boundary_behavior;
+}
+
 template <typename LayerType>
 void SetHasTransformNode(LayerType* layer, bool val) {
   layer->SetHasTransformNode(val);
@@ -1049,6 +1058,7 @@ void AddScrollNodeIfNeeded(
     node.element_id = layer->element_id();
     node.transform_id =
         data_for_children->transform_tree_parent->transform_tree_index();
+    node.scroll_boundary_behavior = GetScrollBoundaryBehavior(layer);
 
     node_id =
         data_for_children->property_trees->scroll_tree.Insert(node, parent_id);