arc: Logging ARC data removal reasons

chrome/browser/chromeos/arc/arc_session_manager.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_ARC_ARC_SESSION_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_SESSION_MANAGER_H_
 
 #include <memory>
 #include <ostream>
 #include <string>
@@ skipping 185 matching lines @@
 
   // Stops ARC without changing ArcEnabled preference.
   void StopArc();
 
   // StopArc(), then EnableArc(). Between them data clear may happens.
   // This is a special method to support enterprise device lost case.
   // This can be called only when ARC is running.
   void StopAndEnableArc();
 
   // Removes the data if ARC is stopped. Otherwise, queue to remove the data
-  // on ARC is stopped.
+  // on ARC is stopped. A log statement with the removal reason must be added
+  // prior to calling RemoveArcData().
   void RemoveArcData();
 
   ArcSupportHost* support_host() { return support_host_.get(); }
 
   // TODO(hidehiko): Get rid of the getter by migration between ArcAuthContext
   // and ArcAuthInfoFetcher.
   ArcAuthContext* auth_context() { return context_.get(); }
 
   void StartArc();
 
@@ skipping 78 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(ArcSessionManager);
 };
 
 // Outputs the stringified |state| to |os|. This is only for logging purposes.
 std::ostream& operator<<(std::ostream& os,
                          const ArcSessionManager::State& state);
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_SESSION_MANAGER_H_