[not for review - epic CL] Adding Elastic+Momentum+Layered scrolling to views::ScrollView

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 3d032fcc50bf7998f0b1382491b6891ad30072a0..d38a720d8462f70c39ab22246ec0dda35cdde1aa 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -49,6 +49,7 @@ class PageScaleAnimation;
 class PictureLayerImpl;
 class TaskRunnerProvider;
 class ResourceProvider;
+class ScrollElasticityHelper;
 class TileManager;
 class UIResourceRequest;
 class VideoFrameControllerClient;
@@ -102,6 +103,8 @@ class CC_EXPORT LayerTreeImpl {
   const gfx::Rect ViewportRectForTilePriority() const;
   std::unique_ptr<ScrollbarAnimationController>
   CreateScrollbarAnimationController(int scroll_layer_id);
+  std::unique_ptr<ScrollElasticityHelper> CreateScrollElasticityHelper(
+      int scroll_layer_id);
   void DidAnimateScrollOffset();
   bool use_gpu_rasterization() const;
   GpuRasterizationStatus GetGpuRasterizationStatus() const;
@@ -209,7 +212,7 @@ class CC_EXPORT LayerTreeImpl {
   void UpdatePropertyTreeScrollingAndAnimationFromMainThread();
   void UpdatePropertyTreeScrollOffset(PropertyTrees* property_trees) {
     property_trees_.scroll_tree.UpdateScrollOffsetMap(
-        &property_trees->scroll_tree.scroll_offset_map(), this);
+        &property_trees->scroll_tree, this);
   }
   void SetPageScaleOnActiveTree(float active_page_scale);
   void PushPageScaleFromMainThread(float page_scale_factor,