Implement CSS: scroll-boundary-behavior

cc/trees/scroll_node.cc

Index: cc/trees/scroll_node.cc
diff --git a/cc/trees/scroll_node.cc b/cc/trees/scroll_node.cc
index 17d73bfc0baaac34ea40e04a354f4850685507b9..db5e6c2e5d046909d2d538a594055c113e3be435 100644
--- a/cc/trees/scroll_node.cc
+++ b/cc/trees/scroll_node.cc
@@ -24,7 +24,9 @@ ScrollNode::ScrollNode()
       should_flatten(false),
       user_scrollable_horizontal(false),
       user_scrollable_vertical(false),
-      transform_id(0) {}
+      transform_id(0),
+      scroll_boundary_behavior(
+          ScrollBoundaryBehavior::kScrollBoundaryBehaviorTypeAuto) {}
 
 ScrollNode::ScrollNode(const ScrollNode& other) = default;
 
@@ -42,7 +44,8 @@ bool ScrollNode::operator==(const ScrollNode& other) const {
          should_flatten == other.should_flatten &&
          user_scrollable_horizontal == other.user_scrollable_horizontal &&
          user_scrollable_vertical == other.user_scrollable_vertical &&
-         element_id == other.element_id && transform_id == other.transform_id;
+         element_id == other.element_id && transform_id == other.transform_id &&
+         scroll_boundary_behavior == other.scroll_boundary_behavior;
 }
 
 void ScrollNode::AsValueInto(base::trace_event::TracedValue* value) const {
@@ -59,6 +62,8 @@ void ScrollNode::AsValueInto(base::trace_event::TracedValue* value) const {
 
   element_id.AddToTracedValue(value);
   value->SetInteger("transform_id", transform_id);
+  value->SetInteger("scroll_boundary_behavior_x", scroll_boundary_behavior.x);
+  value->SetInteger("scroll_boundary_behavior_y", scroll_boundary_behavior.y);
 }
 
 }  // namespace cc