Componentize chrome/browser/network_time

Move chrome/browser/network_time to components/network_time
network_time.h is removed as it's unused.

BUG=371470
TEST=git cl try

Review URL: https://codereview.chromium.org/296453005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274887 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 80 insertions, 0 deletions

diff --git a/components/network_time/network_time_tracker.h b/components/network_time/network_time_tracker.h
new file mode 100644
index 0000000..80fd0c2
--- /dev/null
+++ b/components/network_time/network_time_tracker.h
@@ -0,0 +1,80 @@
+// 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 COMPONENTS_NETWORK_TIME_NETWORK_TIME_TRACKER_H_
+#define COMPONENTS_NETWORK_TIME_NETWORK_TIME_TRACKER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "base/time/time.h"
+
+class PrefRegistrySimple;
+class PrefService;
+
+namespace base {
+class TickClock;
+}
+
+namespace network_time {
+
+// A class that receives network time updates and can provide the network time
+// for a corresponding local time. This class is not thread safe.
+class NetworkTimeTracker {
+ public:
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+  NetworkTimeTracker(scoped_ptr<base::TickClock> tick_clock,
+                     PrefService* pref_service);
+  ~NetworkTimeTracker();
+
+  // Returns the network time corresponding to |time_ticks| if network time
+  // is available. Returns false if no network time is available yet. Can also
+  // return the error range if |uncertainty| isn't NULL.
+  bool GetNetworkTime(base::TimeTicks time_ticks,
+                      base::Time* network_time,
+                      base::TimeDelta* uncertainty) const;
+
+  // Calculates corresponding time ticks according to the given parameters.
+  // 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(base::Time network_time,
+                         base::TimeDelta resolution,
+                         base::TimeDelta latency,
+                         base::TimeTicks post_time);
+
+  bool received_network_time() const {
+    return received_network_time_;
+  }
+
+ private:
+  // For querying current time ticks.
+  scoped_ptr<base::TickClock> tick_clock_;
+
+  PrefService* pref_service_;
+
+  // 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_;
+
+  base::ThreadChecker thread_checker_;
+
+  bool received_network_time_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkTimeTracker);
+};
+
+}  // namespace network_time
+
+#endif  // COMPONENTS_NETWORK_TIME_NETWORK_TIME_TRACKER_H_