Harmonize LayerTreeHost/LayerTreeHostImpl synchronization steps

cc/layers/layer_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/layer_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 262 matching lines @@
   return scroll_tree.ScrollBy(scroll_node, scroll, layer_tree_impl());
 }
 
 void LayerImpl::SetScrollClipLayer(int scroll_clip_layer_id) {
   if (scroll_clip_layer_id_ == scroll_clip_layer_id)
     return;
 
   layer_tree_impl()->UnregisterScrollLayer(this);
   scroll_clip_layer_id_ = scroll_clip_layer_id;
   layer_tree_impl()->RegisterScrollLayer(this);
-
-  // Ensure our viewport layer type is updated.

[chrishtr, 2017/05/15 18:50:45]

Per offline, let's pull this out.

-  layer_tree_impl()->UpdateViewportLayerTypes();
 }
 
 LayerImpl* LayerImpl::scroll_clip_layer() const {
   return layer_tree_impl()->LayerById(scroll_clip_layer_id_);
 }
 
 bool LayerImpl::scrollable() const {
   return scroll_clip_layer_id_ != Layer::INVALID_ID;
 }
 
@@ skipping 677 matching lines @@
 
 ScrollTree& LayerImpl::GetScrollTree() const {
   return GetPropertyTrees()->scroll_tree;
 }
 
 TransformTree& LayerImpl::GetTransformTree() const {
   return GetPropertyTrees()->transform_tree;
 }
 
 }  // namespace cc