cc: Clean up LayerTreeTest and TestHooks.

cc/test/threaded_channel_for_test.h

-// 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.
-
-#ifndef CC_TEST_THREADED_CHANNEL_FOR_TEST_H_
-#define CC_TEST_THREADED_CHANNEL_FOR_TEST_H_
-
-#include "base/macros.h"
-#include "cc/test/test_hooks.h"
-#include "cc/trees/threaded_channel.h"
-
-namespace cc {
-class ProxyImplForTest;
-
-// ThreadedChannel that notifies |test_hooks| of internal actions by ProxyImpl.
-class ThreadedChannelForTest : public ThreadedChannel {
- public:
-  static std::unique_ptr<ThreadedChannelForTest> Create(
-      TestHooks* test_hooks,
-      ProxyMain* proxy_main,
-      TaskRunnerProvider* task_runner_provider);
-
-  ProxyImplForTest* proxy_impl_for_test() { return proxy_impl_for_test_; }
-
- private:
-  ThreadedChannelForTest(TestHooks* test_hooks,
-                         ProxyMain* proxy_main,
-                         TaskRunnerProvider* task_runner_provider);
-
-  std::unique_ptr<ProxyImpl> CreateProxyImpl(
-      ChannelImpl* channel_impl,
-      LayerTreeHost* layer_tree_host,
-      TaskRunnerProvider* task_runner_provider,
-      std::unique_ptr<BeginFrameSource> external_begin_frame_source) override;
-
-  TestHooks* test_hooks_;
-  ProxyImplForTest* proxy_impl_for_test_;
-};
-
-}  // namespace cc
-
-#endif  // CC_TEST_THREADED_CHANNEL_FOR_TEST_H_