Fix compiler warning: "control reaches end of non-void function"

chrome/browser/sync/profile_sync_service.cc

 // Copyright (c) 2012 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/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 987 matching lines @@
   switch (status) {
     case syncer::CONNECTION_OK:
       return AuthError::AuthErrorNone();
       break;
     case syncer::CONNECTION_AUTH_ERROR:
       return AuthError(AuthError::INVALID_GAIA_CREDENTIALS);
       break;
     case syncer::CONNECTION_SERVER_ERROR:
       return AuthError(AuthError::CONNECTION_FAILED);
       break;
-    default:
-      NOTREACHED();
-      return AuthError(AuthError::CONNECTION_FAILED);
   }
+
+  NOTREACHED();
+  return AuthError(AuthError::CONNECTION_FAILED);
 }
 
 }  // namespace
 
 void ProfileSyncService::OnConnectionStatusChange(
     syncer::ConnectionStatus status) {
   const GoogleServiceAuthError auth_error =
       ConnectionStatusToAuthError(status);
   DVLOG(1) << "Connection status change: " << auth_error.ToString();
   UpdateAuthErrorState(auth_error);
@@ skipping 1004 matching lines @@
   // See http://stackoverflow.com/questions/6224121/is-new-this-myclass-undefined-behaviour-after-directly-calling-the-destru.
   ProfileSyncService* old_this = this;
   this->~ProfileSyncService();
   new(old_this) ProfileSyncService(
       new ProfileSyncComponentsFactoryImpl(profile,
                                            CommandLine::ForCurrentProcess()),
       profile,
       signin,
       behavior);
 }