Do nothing on OnSessionStopped if ARC is being restarted.

chrome/browser/chromeos/arc/test/arc_data_removed_waiter.h

 // Copyright 2017 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_ARC_TEST_ARC_DATA_REMOVED_WAITER_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_TEST_ARC_DATA_REMOVED_WAITER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "chrome/browser/chromeos/arc/arc_session_manager.h"
 
 namespace base {
 class RunLoop;
 }
 
 namespace arc {
 
 // Waits for ARC data has been removed.
 class ArcDataRemovedWaiter : public ArcSessionManager::Observer {
  public:
   ArcDataRemovedWaiter();
-  ~ArcDataRemovedWaiter() override;
+  ~ArcDataRemovedWaiter();
 
   // Waits until ARC data is removed. Waiting is end once ArcSessionManager
   // sends OnArcDataRemoved notification.
   void Wait();
 
  private:
   // ArcSessionManager::Observer:
   void OnArcDataRemoved() override;
 
   std::unique_ptr<base::RunLoop> run_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcDataRemovedWaiter);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_TEST_ARC_DATA_REMOVED_WAITER_H_