[Remote suggestions] Move the throttler into the Scheduler

components/ntp_snippets/remote/remote_suggestions_fetcher_unittest.cc

 // Copyright 2016 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 "components/ntp_snippets/remote/remote_suggestions_fetcher.h"
 
 #include <deque>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 265 matching lines @@
  public:
   explicit RemoteSuggestionsFetcherTestBase(const GURL& gurl)
       : default_variation_params_(
             {{"send_top_languages", "true"}, {"send_user_class", "true"}}),
         params_manager_(ntp_snippets::kStudyName,
                         default_variation_params_,
                         {ntp_snippets::kArticleSuggestionsFeature.name}),
         mock_task_runner_(new base::TestMockTimeTaskRunner()),
         mock_task_runner_handle_(mock_task_runner_),
         test_url_(gurl) {
-    RequestThrottler::RegisterProfilePrefs(utils_.pref_service()->registry());
     UserClassifier::RegisterProfilePrefs(utils_.pref_service()->registry());
     user_classifier_ = base::MakeUnique<UserClassifier>(utils_.pref_service());
     // Increase initial time such that ticks are non-zero.
     mock_task_runner_->FastForwardBy(base::TimeDelta::FromMilliseconds(1234));
     ResetFetcher();
   }
 
   void ResetFetcher() {
     scoped_refptr<net::TestURLRequestContextGetter> request_context_getter =
         new net::TestURLRequestContextGetter(mock_task_runner_.get());
@@ skipping 719 matching lines @@
         fetched_categories) {
   if (fetched_categories) {
     // Matchers above aren't any more precise than this, so this is sufficient
     // for test-failure diagnostics.
     return os << "list with " << fetched_categories->size() << " elements";
   }
   return os << "null";
 }
 
 }  // namespace ntp_snippets