Properly initialize last_notification_severity_.

chrome/browser/chromeos/ui/low_disk_notification.h

 // Copyright 2016 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 CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_
 #define CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 43 matching lines @@
   Severity GetSeverity(uint64_t free_disk_bytes);
 
   // Sets the MessageCenter instance to use.  Should only be used in tests.
   void SetMessageCenterForTest(message_center::MessageCenter* message_center);
 
   // Sets the minimum time to wait between notifications of the same severity.
   // Should only be used in tests.
   void SetNotificationIntervalForTest(base::TimeDelta interval);
 
   base::Time last_notification_time_;
-  Severity last_notification_severity_;
+  Severity last_notification_severity_ = NONE;
   message_center::MessageCenter* message_center_;
   base::TimeDelta notification_interval_;
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<LowDiskNotification> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LowDiskNotification);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_UI_LOW_DISK_NOTIFICATION_H_