Introduce separate client and init path for single-threaded cc

cc/layers/texture_layer_unittest.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/texture_layer.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 25 matching lines @@
 using ::testing::Mock;
 using ::testing::_;
 using ::testing::AtLeast;
 using ::testing::AnyNumber;
 
 namespace cc {
 namespace {
 
 class MockLayerTreeHost : public LayerTreeHost {
  public:
-  explicit MockLayerTreeHost(LayerTreeHostClient* client)
+  explicit MockLayerTreeHost(FakeLayerTreeHostClient* client)
       : LayerTreeHost(client, NULL, LayerTreeSettings()) {
-    Initialize(NULL);
+    InitializeSingleThreaded(client);
   }
 
   MOCK_METHOD0(AcquireLayerTextures, void());
   MOCK_METHOD0(SetNeedsCommit, void());
   MOCK_METHOD0(SetNeedsUpdateLayers, void());
   MOCK_METHOD0(StartRateLimiter, void());
   MOCK_METHOD0(StopRateLimiter, void());
 };
 
 class TextureLayerTest : public testing::Test {
@@ skipping 2085 matching lines @@
   int callback_count_;
   scoped_refptr<Layer> root_;
   scoped_refptr<TextureLayer> layer_;
 };
 
 SINGLE_AND_MULTI_THREAD_DIRECT_RENDERER_TEST_F(
     TextureLayerWithMailboxImplThreadDeleted);
 
 }  // namespace
 }  // namespace cc