Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/test/layer_tree_test.cc

 // Copyright 2011 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/test/layer_tree_test.h"
 
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
@@ skipping 912 matching lines @@
   LayerTreeHost* host = IsRemoteTest() ? remote_client_layer_tree_host_.get()
                                        : layer_tree_host_.get();
 
   // If this fails, the test has ended and there is no task runners to find
   // anymore.
   DCHECK(host);
 
   return host->task_runner_provider();
 }
 
+LayerTree* LayerTreeTest::layer_tree() {
+  return layer_tree_host()->GetLayerTree();
+}
+
 LayerTreeHost* LayerTreeTest::layer_tree_host() {
   DCHECK(task_runner_provider()->IsMainThread() ||
          task_runner_provider()->IsMainThreadBlocked());
   return layer_tree_host_.get();
 }
 
 LayerTreeHost* LayerTreeTest::remote_client_layer_tree_host() {
   DCHECK(IsRemoteTest());
   DCHECK(task_runner_provider()->IsMainThread() ||
          task_runner_provider()->IsMainThreadBlocked());
   return remote_client_layer_tree_host_.get();
 }
 
 }  // namespace cc