Merge NetworkTimeNotifier to NetworkTimeTracker

net/base/network_time_notifier.h

-// Copyright (c) 2013 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 NET_BASE_NETWORK_TIME_NOTIFIER_H_
-#define NET_BASE_NETWORK_TIME_NOTIFIER_H_
-
-#include <vector>
-
-#include "base/callback.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
-#include "base/time/tick_clock.h"
-#include "base/time/time.h"
-#include "net/base/net_export.h"
-
-namespace net {
-
-// A class that receives updates for and maintains network time. Network time
-// sources can pass updates through UpdateNetworkTime, and network time
-// consumers can register as observers. This class is not thread-safe.
-class NET_EXPORT NetworkTimeNotifier {
- public:
-  // Callback for observers to receive network time updates.
-  // The parameters are:
-  // const base::Time& network_time - the new network time.
-  // const base::TimeTicks& network_time_ticks - the ticks time that corresponds
-  //     with |network_time|.
-  // const base::TimeDelta& network_time_uncertainty - the uncertainty
-  //     associated with the new network time.
-  typedef base::Callback<void(const base::Time&,
-                              const base::TimeTicks&,
-                              const base::TimeDelta&)> ObserverCallback;
-
-  // Takes ownership of |tick_clock|.
-  explicit NetworkTimeNotifier(scoped_ptr<base::TickClock> tick_clock);
-  ~NetworkTimeNotifier();
-
-  // Calculates corresponding time ticks according to the given parameters and
-  // notifies observers. The provided |network_time| is precise at the given
-  // |resolution| and represent the time between now and up to |latency| +
-  // (now - |post_time|) ago.
-  void UpdateNetworkTime(const base::Time& network_time,
-                         const base::TimeDelta& resolution,
-                         const base::TimeDelta& latency,
-                         const base::TimeTicks& post_time);
-
-  // |observer_callback| will invoked every time the network time is updated, or
-  // if a network time is already available when AddObserver is called.
-  void AddObserver(const ObserverCallback& observer_callback);
-
- private:
-  base::ThreadChecker thread_checker_;
-
-  // For querying current time ticks.
-  scoped_ptr<base::TickClock> tick_clock_;
-
-  // The network time based on last call to UpdateNetworkTime().
-  base::Time network_time_;
-
-  // The estimated local time from |tick_clock| that corresponds with
-  // |network_time|. Assumes the actual network time measurement was performed
-  // midway through the latency time, and does not account for suspect/resume
-  // events since the network time was measured.
-  // See UpdateNetworkTime(..) implementation for details.
-  base::TimeTicks network_time_ticks_;
-
-  // Uncertainty of |network_time_| based on added inaccuracies/resolution.
-  // See UpdateNetworkTime(..) implementation for details.
-  base::TimeDelta network_time_uncertainty_;
-
-  // List of network time update observers.
-  // A vector of callbacks is used, rather than an ObserverList, so that the
-  // lifetime of the observer can be bound to the callback.
-  std::vector<ObserverCallback> observers_;
-
-  DISALLOW_COPY_AND_ASSIGN(NetworkTimeNotifier);
-};
-
-}  // namespace net
-
-#endif  // NET_BASE_NETWORK_TIME_NOTIFIER_H_