Remove support for custom overscroll background

mojo/services/html_viewer/weblayertreeview_impl.cc

Index: mojo/services/html_viewer/weblayertreeview_impl.cc
diff --git a/mojo/services/html_viewer/weblayertreeview_impl.cc b/mojo/services/html_viewer/weblayertreeview_impl.cc
index a0e26f8b71914b2440adfff6d455c7ec9a010f69..237e7dca772337db557fd7c36781629992ec4e33 100644
--- a/mojo/services/html_viewer/weblayertreeview_impl.cc
+++ b/mojo/services/html_viewer/weblayertreeview_impl.cc
@@ -155,10 +155,6 @@ void WebLayerTreeViewImpl::setHasTransparentBackground(
   layer_tree_host_->set_has_transparent_background(has_transparent_background);
 }
 
-void WebLayerTreeViewImpl::setOverhangBitmap(const SkBitmap& bitmap) {
-  layer_tree_host_->SetOverhangBitmap(bitmap);
-}
-
 void WebLayerTreeViewImpl::setVisible(bool visible) {
   layer_tree_host_->SetVisible(visible);
 }