Delta from the first fix.

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 1900e031316df341011e8fd43279b67b519961b6..3f92db8dcef53cd1e293a87a9030ad62dcf5ae98 100644
--- a/chrome/browser/extensions/api/alarms/alarm_manager.h
+++ b/chrome/browser/extensions/api/alarms/alarm_manager.h
@@ -215,9 +215,11 @@ class AlarmManager
   // extension.
   ReadyMap ready_actions_;
 
-  // The previous and next time that alarms were and will be run.
+  // The previous time that alarms were run.
   base::Time last_poll_time_;
-  base::Time next_poll_time_;
+
+  // Next poll's time. Used only by unit tests.
+  base::Time test_next_poll_time_;
 
   DISALLOW_COPY_AND_ASSIGN(AlarmManager);
 };