Implement CSS: scroll-boundary-behavior

cc/layers/layer.cc

Index: cc/layers/layer.cc
diff --git a/cc/layers/layer.cc b/cc/layers/layer.cc
index 223fc65c0c1b7f3d295d643ee26d871de324e14f..b2a1aa137ca76af0de1024dde1bc0fceab2d78a3 100644
--- a/cc/layers/layer.cc
+++ b/cc/layers/layer.cc
@@ -64,7 +64,8 @@ Layer::Inputs::Inputs(int layer_id)
       clip_parent(nullptr),
       has_will_change_transform_hint(false),
       hide_layer_and_subtree(false),
-      client(nullptr) {}
+      client(nullptr),
+      scroll_boundary_behavior(SCROLL_BOUNDARY_BEHAVIOR_PROPAGATE) {}
 
 Layer::Inputs::~Inputs() {}
 
@@ -310,6 +311,14 @@ void Layer::SetBounds(const gfx::Size& size) {
   SetNeedsCommit();
 }
 
+void Layer::SetScrollBoundaryBehavior(ScrollBoundaryBehavior behavior) {
+  if (scrollBoundaryBehavior() == behavior)
+    return;
+  inputs_.scroll_boundary_behavior = behavior;
+
+  SetNeedsCommit();
+}
+
 Layer* Layer::RootLayer() {
   Layer* layer = this;
   while (layer->parent())
@@ -1190,6 +1199,7 @@ void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->SetUpdateRect(inputs_.update_rect);
 
   layer->SetHasWillChangeTransformHint(has_will_change_transform_hint());
+  layer->SetScrollBoundaryBehavior(inputs_.scroll_boundary_behavior);
   layer->SetNeedsPushProperties();
 
   // Reset any state that should be cleared for the next update.