Support multiple Observer instances for ArcSupportHost.

chrome/browser/chromeos/arc/arc_auth_service.cc

 // Copyright 2015 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 "chrome/browser/chromeos/arc/arc_auth_service.h"
 
 #include <utility>
 
 #include "ash/common/shelf/shelf_delegate.h"
 #include "ash/common/wm_shell.h"
@@ skipping 590 matching lines @@
   // ARC support Chrome app is rarely used (only opt-in and re-auth flow).
   // So, it may be better to initialize it lazily.
   // TODO(hidehiko): Revisit to think about lazy initialization.
   //
   // Don't show UI for ARC Kiosk because the only one UI in kiosk mode must
   // be the kiosk app. In case of error the UI will be useless as well, because
   // in typical use case there will be no one nearby the kiosk device, who can
   // do some action to solve the problem be means of UI.
   if (!g_disable_ui_for_testing && !IsOptInVerificationDisabled() &&
       !IsArcKioskMode()) {
+    DCHECK(!support_host_);
     support_host_ = base::MakeUnique<ArcSupportHost>(profile_);
     support_host_->AddObserver(this);
 
     preference_handler_ = base::MakeUnique<arc::ArcOptInPreferenceHandler>(
         this, profile_->GetPrefs());
     // This automatically updates all preferences.
     preference_handler_->Start();
   }
 
   DCHECK_EQ(State::NOT_INITIALIZED, state_);
@@ skipping 28 matching lines @@
     return;
 
   pref_service_syncable->RemoveObserver(this);
 
   if (IsArcEnabled())
     OnOptInPreferenceChanged();
 }
 
 void ArcAuthService::Shutdown() {
   ShutdownBridge();
-  if (support_host_)
+  if (support_host_) {
     support_host_->Close();
+    support_host_->RemoveObserver(this);
+    support_host_.reset();
+  }
   if (profile_) {
     sync_preferences::PrefServiceSyncable* pref_service_syncable =
         PrefServiceSyncableFromProfile(profile_);
     pref_service_syncable->RemoveObserver(this);
     pref_service_syncable->RemoveSyncedPrefObserver(prefs::kArcEnabled, this);
   }
   pref_change_registrar_.RemoveAll();
   context_.reset();
   profile_ = nullptr;
   arc_robot_auth_.reset();
@@ skipping 399 matching lines @@
       return os << "ACTIVE";
   }
 
   // Some compiler reports an error even if all values of an enum-class are
   // covered indivisually in a switch statement.
   NOTREACHED();
   return os;
 }
 
 }  // namespace arc