Do not reschedule all alarms when adding a new alarm

chrome/browser/extensions/api/alarms/alarm_manager.h

Index: chrome/browser/extensions/api/alarms/alarm_manager.h
diff --git a/chrome/browser/extensions/api/alarms/alarm_manager.h b/chrome/browser/extensions/api/alarms/alarm_manager.h
index 8c0666c74f572ea001506adb1afb1d91858a2ed7..0d04bbf044273a46662e2c8e48d5dd37592a17b5 100644
--- a/chrome/browser/extensions/api/alarms/alarm_manager.h
+++ b/chrome/browser/extensions/api/alarms/alarm_manager.h
@@ -184,6 +184,10 @@ class AlarmManager
   void ReadFromStorage(const std::string& extension_id,
                        scoped_ptr<base::Value> value);
 
+  // Set the timer to go off at the specified |time|, and set |next_poll_time|
+  // appropriately.
+  void SetNextPollTime(const base::Time& time);
+
   // Schedules the next poll of alarms for when the next soonest alarm runs,
   // but not more often than the minimum granularity of all alarms.
   void ScheduleNextPoll();
@@ -226,8 +230,8 @@ class AlarmManager
   // The previous time that alarms were run.
   base::Time last_poll_time_;
 
-  // Next poll's time. Used only by unit tests.
-  base::Time test_next_poll_time_;
+  // Next poll's time.
+  base::Time next_poll_time_;
 
   DISALLOW_COPY_AND_ASSIGN(AlarmManager);
 };