[NTP Snippets] Schedule periodic fetching

components/ntp_snippets/ntp_snippets_service_unittest.cc

 // Copyright 2015 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 "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "components/ntp_snippets/ntp_snippet.h"
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
@@ skipping 44 matching lines @@
   scoped_refptr<base::SingleThreadTaskRunner> task_runner(
       base::ThreadTaskRunnerHandle::Get());
   scoped_refptr<net::TestURLRequestContextGetter> request_context_getter =
       new net::TestURLRequestContextGetter(task_runner.get());
   FakeProfileOAuth2TokenService* token_service =
       new FakeProfileOAuth2TokenService();
   FakeSigninManagerBase* signin_manager =  new FakeSigninManagerBase(
       new TestSigninClient(nullptr), new AccountTrackerService());
 
   scoped_ptr<NTPSnippetsService> service(
-      new NTPSnippetsService(task_runner.get(), language_code,
+      new NTPSnippetsService(task_runner.get(), language_code, nullptr,
         make_scoped_ptr(new NTPSnippetsFetcher(task_runner.get(),
           signin_manager, token_service, request_context_getter,
           base::FilePath()))));
   return service;
 }
 
 TEST_F(NTPSnippetsServiceTest, Create) {
   std::string language_code("fr");
   scoped_ptr<NTPSnippetsService> service(CreateSnippetService(language_code));
   EXPECT_FALSE(service->is_loaded());
@@ skipping 87 matching lines @@
   EXPECT_TRUE(service->LoadFromJSONString(json_str));
 
   SnippetObserver observer;
   service->AddObserver(&observer);
 
   EXPECT_TRUE(observer.loaded_);
 
   service->RemoveObserver(&observer);
 }
 }  // namespace ntp_snippets