Remove support for custom overscroll background

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 98d7e4b0e004c9c4aa913a33d8cba0c6a9d43f48..911e8123ddc7994173dba15e389f4f48321fb925 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -356,9 +356,6 @@ class CC_EXPORT LayerTreeHostImpl
   void SetViewportSize(const gfx::Size& device_viewport_size);
   gfx::Size device_viewport_size() const { return device_viewport_size_; }
 
-  void SetOverhangUIResource(UIResourceId overhang_ui_resource_id,
-                             const gfx::Size& overhang_ui_resource_size);
-
   void SetDeviceScaleFactor(float device_scale_factor);
   float device_scale_factor() const { return device_scale_factor_; }
 
@@ -686,10 +683,6 @@ class CC_EXPORT LayerTreeHostImpl
   // pageScaleFactor=1.
   float device_scale_factor_;
 
-  // UI resource to use for drawing overhang gutters.
-  UIResourceId overhang_ui_resource_id_;
-  gfx::Size overhang_ui_resource_size_;
-
   // Optional top-level constraints that can be set by the OutputSurface.
   // - external_transform_ applies a transform above the root layer
   // - external_viewport_ is used DrawProperties, tile management and