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

chrome/browser/sync/profile_sync_service_preference_unittest.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 <map>
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
@@ skipping 87 matching lines @@
     profile_.reset(new TestingProfile());
     profile_->CreateRequestContext();
     prefs_ = profile_->GetTestingPrefService();
 
     prefs_->RegisterStringPref(not_synced_preference_name_.c_str(),
                                not_synced_preference_default_value_,
                                PrefService::UNSYNCABLE_PREF);
   }
 
   virtual void TearDown() {
+    service_->Shutdown();
     service_.reset();
     profile_.reset();
     AbstractProfileSyncServiceTest::TearDown();
   }
 
   bool StartSyncService(const base::Closure& callback,
                         bool will_fail_association) {
     if (service_.get())
       return false;
 
@@ skipping 457 matching lines @@
   EXPECT_FALSE(pref->IsDefaultValue());
   // There should be no synced value.
   EXPECT_TRUE(GetSyncedValue(prefs::kHomePage) == NULL);
   // Switch kHomePage back to unmanaged.
   profile_->GetTestingPrefService()->RemoveManagedPref(prefs::kHomePage);
   // The original value should be picked up.
   EXPECT_TRUE(pref->IsDefaultValue());
   // There should still be no synced value.
   EXPECT_TRUE(GetSyncedValue(prefs::kHomePage) == NULL);
 }