Implement CSS: scroll-boundary-behavior

cc/trees/scroll_node.cc

 // 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.
 
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/base/math_util.h"
 #include "cc/input/main_thread_scrolling_reason.h"
 #include "cc/layers/layer.h"
 #include "cc/trees/element_id.h"
 #include "cc/trees/property_tree.h"
 #include "cc/trees/scroll_node.h"
 
 namespace cc {
 
 ScrollNode::ScrollNode()
     : id(ScrollTree::kInvalidNodeId),
       parent_id(ScrollTree::kInvalidNodeId),
       owning_layer_id(Layer::INVALID_ID),
       scrollable(false),
       main_thread_scrolling_reasons(
           MainThreadScrollingReason::kNotScrollingOnMain),
       max_scroll_offset_affected_by_page_scale(false),
       scrolls_inner_viewport(false),
       scrolls_outer_viewport(false),
       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;
 
 bool ScrollNode::operator==(const ScrollNode& other) const {
   return id == other.id && parent_id == other.parent_id &&
          owning_layer_id == other.owning_layer_id &&
          scrollable == other.scrollable &&
          main_thread_scrolling_reasons == other.main_thread_scrolling_reasons &&
          non_fast_scrollable_region == other.non_fast_scrollable_region &&
          scroll_clip_layer_bounds == other.scroll_clip_layer_bounds &&
          bounds == other.bounds &&
          max_scroll_offset_affected_by_page_scale ==
              other.max_scroll_offset_affected_by_page_scale &&
          scrolls_inner_viewport == other.scrolls_inner_viewport &&
          scrolls_outer_viewport == other.scrolls_outer_viewport &&
          offset_to_transform_parent == other.offset_to_transform_parent &&
          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 {
   value->SetInteger("id", id);
   value->SetInteger("parent_id", parent_id);
   value->SetInteger("owning_layer_id", owning_layer_id);
   value->SetBoolean("scrollable", scrollable);
   MathUtil::AddToTracedValue("scroll_clip_layer_bounds",
                              scroll_clip_layer_bounds, value);
   MathUtil::AddToTracedValue("bounds", bounds, value);
   MathUtil::AddToTracedValue("offset_to_transform_parent",
                              offset_to_transform_parent, value);
   value->SetBoolean("should_flatten", should_flatten);
   value->SetBoolean("user_scrollable_horizontal", user_scrollable_horizontal);
   value->SetBoolean("user_scrollable_vertical", user_scrollable_vertical);
 
   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