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 050dbf00294a9e283da0a5752a7a38c8f6a95127..f746a6913029ee8055f4af0a3490f053361bed19 100644
--- a/cc/trees/scroll_node.cc
+++ b/cc/trees/scroll_node.cc
@@ -25,7 +25,9 @@ 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;
 
@@ -45,7 +47,8 @@ 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 {
@@ -64,6 +67,8 @@ 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