Add a disable-arc-data-wipe flag.

components/arc/user_data/arc_user_data_service.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 "components/arc/user_data/arc_user_data_service.h"
 
+#include "base/command_line.h"
+#include "chromeos/chromeos_switches.h"
 #include "chromeos/cryptohome/cryptohome_parameters.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "components/prefs/pref_member.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "components/user_manager/user_manager.h"
 
 namespace arc {
 
 ArcUserDataService::ArcUserDataService(
@@ skipping 25 matching lines @@
   }
   ClearIfDisabled();
 }
 
 void ArcUserDataService::ClearIfDisabled() {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (arc_bridge_service()->state() != ArcBridgeService::State::STOPPED) {
     LOG(ERROR) << "ARC instance not stopped, user data can't be cleared";
     return;
   }
-  if (arc_enabled_pref_->GetValue())
+  if (arc_enabled_pref_->GetValue() ||
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          chromeos::switches::kDisableArcDataWipe))

[Yusuke Sato, 2016/07/05 03:52:41]

nit: can you add {}? IIUC arc/ usually uses {} when the condition is multi-line.

[dspaid, 2016/07/05 03:59:04]

Done.

     return;
   const cryptohome::Identification cryptohome_id(primary_user_account_id_);
   chromeos::SessionManagerClient* session_manager_client =
       chromeos::DBusThreadManager::Get()->GetSessionManagerClient();
   session_manager_client->RemoveArcData(cryptohome_id);
 }
 
 }  // namespace arc