Move LayerSorter to exist locally only in layer_tree_host_common

cc/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/layer_tree_host.h"
 
 #include "base/synchronization/lock.h"
 #include "cc/content_layer.h"
 #include "cc/content_layer_client.h"
+#include "cc/layer_impl.h"
 #include "cc/layer_tree_host_impl.h"
 #include "cc/output_surface.h"
 #include "cc/single_thread_proxy.h"
 #include "cc/test/fake_content_layer_client.h"
 #include "cc/test/fake_layer_tree_host_client.h"
 #include "cc/test/fake_proxy.h"
 #include "cc/test/fake_web_compositor_output_surface.h"
 #include "cc/test/geometry_test_utils.h"
 #include "cc/test/layer_tree_test_common.h"
 #include "cc/test/occlusion_tracker_test_common.h"
@@ skipping 3331 matching lines @@
     LayerTreeSettings settings;
     settings.maxPartialTextureUpdates = 4;
 
     scoped_ptr<LayerTreeHost> host = LayerTreeHost::create(&client, settings, scoped_ptr<Thread>());
     EXPECT_TRUE(host->initializeRendererIfNeeded());
     EXPECT_EQ(4u, host->settings().maxPartialTextureUpdates);
 }
 
 }  // namespace
 }  // namespace cc