Do nothing on OnSessionStopped if ARC is being restarted.

chrome/browser/chromeos/arc/arc_session_manager_browsertest.cc

 // 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.
 
 #include <memory>
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 52 matching lines @@
 
 }  // namespace
 
 namespace arc {
 
 // Waits for the "arc.enabled" preference value from true to false.
 class ArcPlayStoreDisabledWaiter : public ArcSessionManager::Observer {
  public:
   ArcPlayStoreDisabledWaiter() { ArcSessionManager::Get()->AddObserver(this); }
 
-  ~ArcPlayStoreDisabledWaiter() override {
+  ~ArcPlayStoreDisabledWaiter() {
     ArcSessionManager::Get()->RemoveObserver(this);
   }
 
   void Wait() {
     base::RunLoop run_loop;
     base::AutoReset<base::RunLoop*> reset(&run_loop_, &run_loop);
     run_loop.Run();
   }
 
  private:
@@ skipping 145 matching lines @@
                                                    base::Time::Max());
   ArcPlayStoreDisabledWaiter().Wait();
   ASSERT_EQ(ArcSessionManager::State::REMOVING_DATA_DIR,
             ArcSessionManager::Get()->state());
   ArcDataRemovedWaiter().Wait();
   ASSERT_EQ(ArcSessionManager::State::STOPPED,
             ArcSessionManager::Get()->state());
 }
 
 }  // namespace arc