Implement CSS: scroll-boundary-behavior

cc/trees/scroll_node.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_TREES_SCROLL_NODE_H_
 #define CC_TREES_SCROLL_NODE_H_
 
 #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 {
 namespace trace_event {
 class TracedValue;
 }  // namespace trace_event
 }  // namespace base
 
 namespace cc {
 
@@ skipping 34 matching lines @@
   // This offset is used when |scrollable| is false and there isn't a transform
   // node already present that covers this offset.
   gfx::Vector2dF offset_to_transform_parent;
 
   bool should_flatten;
   bool user_scrollable_horizontal;
   bool user_scrollable_vertical;
   ElementId element_id;
   int transform_id;
 
+  ScrollBoundaryBehavior scroll_boundary_behavior;
+
   bool operator==(const ScrollNode& other) const;
   void AsValueInto(base::trace_event::TracedValue* value) const;
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_SCROLL_NODE_H_