components: Introduce AlarmTimer class and use it for GCM heartbeat

base/timer/timer.h

 // Copyright (c) 2012 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.
 
 // OneShotTimer and RepeatingTimer provide a simple timer API.  As the names
 // suggest, OneShotTimer calls you back once after a time delay expires.
 // RepeatingTimer on the other hand calls you back periodically with the
 // prescribed time interval.
 //
 // OneShotTimer and RepeatingTimer both cancel the timer when they go out of
@@ skipping 93 matching lines @@
   const base::Closure& user_task() const { return user_task_; }
   const TimeTicks& desired_run_time() const { return desired_run_time_; }
 
  protected:
   // Used to initiate a new delayed task.  This has the side-effect of disabling
   // scheduled_task_ if it is non-null.
   void SetTaskInfo(const tracked_objects::Location& posted_from,
                    TimeDelta delay,
                    const base::Closure& user_task);
 
+  void set_user_task(const Closure& task) { user_task_ = task; }
+  void set_desired_run_time(TimeTicks desired) { desired_run_time_ = desired; }
+  void set_is_running(bool running) { is_running_ = running; }
+
+  const tracked_objects::Location& posted_from() { return posted_from_; }

[Lei Zhang, 2014/10/24 00:44:49]

this can be a const method, same for is_running().

[Chirantan Ekbote, 2014/10/24 01:04:13]

Done.

+
   bool retain_user_task() const { return retain_user_task_; }
   bool is_repeating() const { return is_repeating_; }
 
+  bool is_running() { return is_running_; }

[Lei Zhang, 2014/10/24 00:44:49]

nit: group with the other getters, and put blank line above private:

[Chirantan Ekbote, 2014/10/24 01:04:13]

Done.

  private:
   friend class BaseTimerTaskInternal;
 
   // Allocates a new scheduled_task_ and posts it on the current MessageLoop
   // with the given |delay|. scheduled_task_ must be NULL. scheduled_run_time_
   // and desired_run_time_ are reset to Now() + delay.
   void PostNewScheduledTask(TimeDelta delay);
 
   // Disable scheduled_task_ and abandon it so that it no longer refers back to
   // this object.
@@ skipping 111 matching lines @@
       : Timer(posted_from, delay,
               base::Bind(method, base::Unretained(receiver)),
               false) {}
 
   void Reset() { Timer::Reset(); }
 };
 
 }  // namespace base
 
 #endif  // BASE_TIMER_TIMER_H_