Remove parts of //cc we aren't using

cc/base/unique_notifier.h

-// Copyright 2014 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_UNIQUE_NOTIFIER_H_
-#define CC_BASE_UNIQUE_NOTIFIER_H_
-
-#include "base/callback.h"
-#include "base/memory/weak_ptr.h"
-#include "cc/base/cc_export.h"
-
-namespace base {
-class SequencedTaskRunner;
-}  // namespace base
-
-namespace cc {
-
-class CC_EXPORT UniqueNotifier {
- public:
-  // Configure this notifier to issue the |closure| notification when scheduled.
-  UniqueNotifier(base::SequencedTaskRunner* task_runner,
-                 const base::Closure& closure);
-
-  // Destroying the notifier will ensure that no further notifications will
-  // happen from this class.
-  ~UniqueNotifier();
-
-  // Schedule a notification to be run. If another notification is already
-  // pending, then only one notification will take place.
-  void Schedule();
-
- private:
-  void Notify();
-
-  // TODO(dcheng): How come this doesn't need to hold a ref to the task runner?
-  base::SequencedTaskRunner* task_runner_;
-  base::Closure closure_;
-  bool notification_pending_;
-
-  base::WeakPtrFactory<UniqueNotifier> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(UniqueNotifier);
-};
-
-}  // namespace cc
-
-#endif  // CC_BASE_UNIQUE_NOTIFIER_H_