components: Introduce AlarmTimer class and use it for GCM heartbeat

This adds the AlarmTimer class to components, which is capable of waking
up the system from suspend on platforms that support this operation
(currently only Chrome OS with linux version 3.11 or higher).  On all
other platforms, the AlarmTimer behaves exactly the same as a regular
Timer.

BUG=crosbug.com/p/32272

Review URL: https://codereview.chromium.org/641943002

Cr-Commit-Position: refs/heads/master@{#301175}

1 files changed, 6 insertions, 0 deletions

diff --git a/base/timer/timer.h b/base/timer/timer.h
index 6d282ee..4ef2f45 100644
--- a/base/timer/timer.h
+++ b/base/timer/timer.h
@@ -111,8 +111,14 @@ class BASE_EXPORT Timer {
                    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() const { return posted_from_; }
   bool retain_user_task() const { return retain_user_task_; }
   bool is_repeating() const { return is_repeating_; }
+  bool is_running() const { return is_running_; }
 
  private:
   friend class BaseTimerTaskInternal;