Fixes that host restriction was sometimes applied even when switched off.

components/ntp_snippets/ntp_snippets_service.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 "components/ntp_snippets/ntp_snippets_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <utility>
 
@@ skipping 168 matching lines @@
 void NTPSnippetsService::RegisterProfilePrefs(PrefRegistrySimple* registry) {
   registry->RegisterListPref(prefs::kSnippets);
   registry->RegisterListPref(prefs::kDiscardedSnippets);
   registry->RegisterListPref(prefs::kSnippetHosts);
 }
 
 void NTPSnippetsService::Init(bool enabled) {
   enabled_ = enabled;
   if (enabled_) {
     // |suggestions_service_| can be null in tests.
-    if (suggestions_service_) {
+    if (snippets_fetcher_->UseHostRestriction() && suggestions_service_) {
       suggestions_service_subscription_ = suggestions_service_->AddCallback(
           base::Bind(&NTPSnippetsService::OnSuggestionsChanged,
                      base::Unretained(this)));
     }
 
     // Get any existing snippets immediately from prefs.
     LoadDiscardedSnippetsFromPrefs();
     LoadSnippetsFromPrefs();
 
     // If we don't have any snippets yet, start a fetch.
@@ skipping 293 matching lines @@
     if (snippet->expiry_date() < next_expiry)
       next_expiry = snippet->expiry_date();
   }
   DCHECK_GT(next_expiry, expiry);
   expiry_timer_.Start(FROM_HERE, next_expiry - expiry,
                       base::Bind(&NTPSnippetsService::LoadingSnippetsFinished,
                                  base::Unretained(this)));
 }
 
 }  // namespace ntp_snippets