Refactor MutatorHostClient from LayerTreeHost to LayerTree.

cc/trees/layer_tree_host_unittest.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/trees/layer_tree_host.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 5588 matching lines @@
     std::unique_ptr<SwapPromise> swap_promise1(
         new TestSwapPromise(&swap_promise_result_[1]));
     layer_tree_host()->QueueSwapPromise(std::move(swap_promise1));
     layer_tree_host()->SetNeedsCommit();
     layer_tree_host()->Composite(base::TimeTicks::Now());
 
     // Fail to draw (not visible).
     std::unique_ptr<SwapPromise> swap_promise2(
         new TestSwapPromise(&swap_promise_result_[2]));
     layer_tree_host()->QueueSwapPromise(std::move(swap_promise2));
-    layer_tree_host()->SetNeedsDisplayOnAllLayers();
+    layer_tree()->SetNeedsDisplayOnAllLayers();
     layer_tree_host()->SetVisible(false);
     layer_tree_host()->Composite(base::TimeTicks::Now());
 
     EndTest();
   }
 
   void DidCommit() override {
     commit_count_++;
     ASSERT_LE(commit_count_, 3);
   }
@@ skipping 1431 matching lines @@
  private:
   FakeContentLayerClient client_;
   const gfx::Size viewport_size_;
   const gfx::Size large_image_size_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(GpuRasterizationSucceedsWithLargeImage);
 
 }  // namespace
 }  // namespace cc