[exp] cc: Introduce cc::CompositorMutator.

content/test/web_layer_tree_view_impl_for_testing.cc

 // Copyright 2013 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 "content/test/web_layer_tree_view_impl_for_testing.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/synchronization/lock.h"
 #include "cc/base/switches.h"
@@ skipping 26 matching lines @@
 void WebLayerTreeViewImplForTesting::Initialize() {
   cc::LayerTreeSettings settings;
 
   // For web contents, layer transforms should scale up the contents of layers
   // to keep content always crisp when possible.
   settings.layer_transforms_should_scale_layer_contents = true;
 
   // Accelerated animations are enabled for unit tests.
   settings.accelerated_animation_enabled = true;
   layer_tree_host_ = cc::LayerTreeHost::CreateSingleThreaded(
-      this,
-      this,
-      nullptr,
-      nullptr,
-      settings,
-      base::MessageLoopProxy::current(),
-      nullptr);
+      this, this, nullptr, nullptr, nullptr, settings,
+      base::MessageLoopProxy::current(), nullptr);
   DCHECK(layer_tree_host_);
 }
 
 void WebLayerTreeViewImplForTesting::setRootLayer(
     const blink::WebLayer& root) {
   layer_tree_host_->SetRootLayer(
       static_cast<const cc_blink::WebLayerImpl*>(&root)->layer());
 }
 
 void WebLayerTreeViewImplForTesting::clearRootLayer() {
@@ skipping 132 matching lines @@
 
 void WebLayerTreeViewImplForTesting::registerSelection(
     const blink::WebSelectionBound& start,
     const blink::WebSelectionBound& end) {
 }
 
 void WebLayerTreeViewImplForTesting::clearSelection() {
 }
 
 }  // namespace content