[Sync] Require ProfileSyncService to have an uninitialized backend on shutdown

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 148 matching lines @@
   chrome::VersionInfo::Channel channel = chrome::VersionInfo::GetChannel();
   if (channel == chrome::VersionInfo::CHANNEL_STABLE ||
       channel == chrome::VersionInfo::CHANNEL_BETA) {
     sync_service_url_ = GURL(kSyncServerUrl);
   }
 #endif
 }
 
 ProfileSyncService::~ProfileSyncService() {
   sync_prefs_.RemoveSyncPrefObserver(this);
-  Shutdown();
+  // Shutdown() should have been called before destruction.
+  CHECK(!backend_initialized_);

[tim (not reviewing), 2012/10/01 21:18:57]

Hmm. I think DCHECK is more appropriate here (using
http://dev.chromium.org/developers/coding-style#TOC-CHECK-DCHECK-and-NOTREACHED-
as guiding principle) Unless this is temporarily a CHECK to see if it's actually
happening?  

 }
 
 bool ProfileSyncService::IsSyncEnabledAndLoggedIn() {
   // Exit if sync is disabled.
   if (IsManaged() || sync_prefs_.IsStartSuppressed())
     return false;
 
   // Sync is logged in if there is a non-empty authenticated username.
   return !signin_->GetAuthenticatedUsername().empty();
 }
@@ skipping 1641 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);
 }