Update from https://crrev.com/317530

cc/input/scroll_elasticity_helper.cc

Index: cc/input/scroll_elasticity_helper.cc
diff --git a/cc/input/scroll_elasticity_helper.cc b/cc/input/scroll_elasticity_helper.cc
index 1e9fe7dff9f59fd482a286d89fc8dc5a613ac2aa..1c496d905318d486c0171c710ff52d74d30d0c82 100644
--- a/cc/input/scroll_elasticity_helper.cc
+++ b/cc/input/scroll_elasticity_helper.cc
@@ -15,6 +15,7 @@ class ScrollElasticityHelperImpl : public ScrollElasticityHelper {
   explicit ScrollElasticityHelperImpl(LayerTreeHostImpl* layer_tree_host_impl);
   ~ScrollElasticityHelperImpl() override;
 
+  bool IsUserScrollable() const override;
   gfx::Vector2dF StretchAmount() const override;
   void SetStretchAmount(const gfx::Vector2dF& stretch_amount) override;
   gfx::ScrollOffset ScrollOffset() const override;
@@ -34,6 +35,14 @@ ScrollElasticityHelperImpl::ScrollElasticityHelperImpl(
 ScrollElasticityHelperImpl::~ScrollElasticityHelperImpl() {
 }
 
+bool ScrollElasticityHelperImpl::IsUserScrollable() const {
+  LayerImpl* layer = layer_tree_host_impl_->OuterViewportScrollLayer();
+  if (!layer)
+    return false;
+  return layer->user_scrollable_horizontal() ||
+         layer->user_scrollable_vertical();
+}
+
 gfx::Vector2dF ScrollElasticityHelperImpl::StretchAmount() const {
   return layer_tree_host_impl_->active_tree()->elastic_overscroll()->Current(
       true);