Make SyncStartupTracker::Observer destructor virtual

chrome/browser/sync/sync_startup_tracker.cc

 // Copyright (c) 2013 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/sync/sync_startup_tracker.h"
+
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
-#include "chrome/browser/sync/sync_startup_tracker.h"
 
 SyncStartupTracker::SyncStartupTracker(Profile* profile, Observer* observer)
     : profile_(profile),
       observer_(observer) {
   ProfileSyncService* service = ProfileSyncServiceFactory::GetForProfile(
       profile_);
   if (service)
     service->AddObserver(this);
 
   CheckServiceState();
@@ skipping 54 matching lines @@
   // to be fetched, exit.
   if (!service->waiting_for_auth() &&
       service->GetAuthError().state() != GoogleServiceAuthError::NONE) {
     return SYNC_STARTUP_ERROR;
   }
 
   // No error detected yet, but the sync backend hasn't started up yet, so
   // we're in the pending state.
   return SYNC_STARTUP_PENDING;
 }