Instant: Use only one hidden WebContents per profile.

chrome/browser/instant/instant_service_factory.cc

 // Copyright 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/instant/instant_service_factory.h"
 
 #include "chrome/browser/instant/instant_service.h"
 #include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "chrome/browser/search_engines/template_url_service_factory.h"
+#include "chrome/browser/themes/theme_service_factory.h"
 
 // static
 InstantService* InstantServiceFactory::GetForProfile(Profile* profile) {
   return static_cast<InstantService*>(
       GetInstance()->GetServiceForProfile(profile, true));
 }
 
 // static
 InstantServiceFactory* InstantServiceFactory::GetInstance() {
   return Singleton<InstantServiceFactory>::get();
 }
 
 InstantServiceFactory::InstantServiceFactory()
     : ProfileKeyedServiceFactory("InstantService",
                                  ProfileDependencyManager::GetInstance()) {
-  // No dependencies.
+  DependsOn(TemplateURLServiceFactory::GetInstance());
+  DependsOn(ThemeServiceFactory::GetInstance());
 }
 
 InstantServiceFactory::~InstantServiceFactory() {
 }
 
 bool InstantServiceFactory::ServiceRedirectedInIncognito() const {
   return true;
 }
 
 ProfileKeyedService* InstantServiceFactory::BuildServiceInstanceFor(
     Profile* profile) const {
   return new InstantService(profile);
 }