Remove DeferBackgroundExtensionCreation field trial and supporting code

chrome/browser/sync/test/integration/sync_app_helper.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/test/integration/sync_app_helper.h"
 
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/test/integration/extensions_helper.h"
@@ skipping 77 matching lines @@
   instance->SetupIfNecessary(sync_datatype_helper::test());
   return instance;
 }
 
 void SyncAppHelper::SetupIfNecessary(SyncTest* test) {
   if (setup_completed_)
     return;
 
   for (int i = 0; i < test->num_clients(); ++i) {
     extensions::ExtensionSystem::Get(
-        test->GetProfile(i))->InitForRegularProfile(true, false);
+        test->GetProfile(i))->InitForRegularProfile(true);
   }
   extensions::ExtensionSystem::Get(
-      test->verifier())->InitForRegularProfile(true, false);
+      test->verifier())->InitForRegularProfile(true);
 
   setup_completed_ = true;
 }
 
 bool SyncAppHelper::AppStatesMatch(Profile* profile1, Profile* profile2) {
   if (!SyncExtensionHelper::GetInstance()->ExtensionStatesMatch(
           profile1, profile2))
     return false;
 
   const AppStateMap& state_map1 = GetAppStates(profile1);
@@ skipping 63 matching lines @@
 }
 
 void SyncAppHelper::FixNTPOrdinalCollisions(Profile* profile) {
   profile->GetExtensionService()->extension_prefs()->app_sorting()->
       FixNTPOrdinalCollisions();
 }
 
 SyncAppHelper::SyncAppHelper() : setup_completed_(false) {}
 
 SyncAppHelper::~SyncAppHelper() {}