Implement CSS: scroll-boundary-behavior

cc/trees/scroll_node.h

Index: cc/trees/scroll_node.h
diff --git a/cc/trees/scroll_node.h b/cc/trees/scroll_node.h
index e9b1d7da6ba1140b9ddfdbb8a23ef5afb13016cf..d257aed7b87229ff972298e700259e3d4af83ebb 100644
--- a/cc/trees/scroll_node.h
+++ b/cc/trees/scroll_node.h
@@ -8,6 +8,7 @@
 #include "cc/base/filter_operations.h"
 #include "cc/base/region.h"
 #include "cc/cc_export.h"
+#include "cc/input/scroll_boundary_behavior.h"
 #include "ui/gfx/geometry/size.h"
 
 namespace base {
@@ -56,6 +57,8 @@ struct CC_EXPORT ScrollNode {
   ElementId element_id;
   int transform_id;
 
+  ScrollBoundaryBehavior scroll_boundary_behavior;
+
   bool operator==(const ScrollNode& other) const;
   void AsValueInto(base::trace_event::TracedValue* value) const;
 };