cc: Remove cc::Thread and cc::ThreadImpl.

cc/base/thread_impl.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_BASE_THREAD_IMPL_H_
-#define CC_BASE_THREAD_IMPL_H_
-
-#include "base/callback.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop_proxy.h"
-#include "cc/base/cc_export.h"
-#include "cc/base/thread.h"
-
-namespace cc {
-
-// Implements cc::Thread in terms of base::MessageLoopProxy.
-class CC_EXPORT ThreadImpl : public Thread {
- public:
-  // Creates a ThreadImpl wrapping the current thread.
-  static scoped_ptr<cc::Thread> CreateForCurrentThread();
-
-  // Creates a Thread wrapping a non-current thread.
-  static scoped_ptr<cc::Thread> CreateForDifferentThread(
-      scoped_refptr<base::MessageLoopProxy> thread);
-
-  virtual ~ThreadImpl();
-
-  virtual void PostTask(base::Closure cb) OVERRIDE;
-  virtual void PostDelayedTask(base::Closure cb, base::TimeDelta delay)
-      OVERRIDE;
-  virtual bool BelongsToCurrentThread() const OVERRIDE;
-  virtual base::SingleThreadTaskRunner* TaskRunner() OVERRIDE;
-
- private:
-  explicit ThreadImpl(scoped_refptr<base::MessageLoopProxy> thread);
-
-  scoped_refptr<base::MessageLoopProxy> thread_;
-
-  DISALLOW_COPY_AND_ASSIGN(ThreadImpl);
-};
-
-}  // namespace cc
-
-#endif  // CC_BASE_THREAD_IMPL_H_