[NTP::Push] Add Content Suggestions GCM App Handler

components/ntp_snippets/pref_names.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/pref_names.h"
 
 namespace ntp_snippets {
 namespace prefs {
 
 const char kEnableSnippets[] = "ntp_snippets.enable";
@@ skipping 66 matching lines @@
     "ntp_suggestions.user_classifier.last_time_to_use_suggestions";
 
 const char kClickBasedCategoryRankerOrderWithClicks[] =
     "ntp_suggestions.click_based_category_ranker.category_order_with_clicks";
 const char kClickBasedCategoryRankerLastDecayTime[] =
     "ntp_suggestions.click_based_category_ranker.last_decay_time";
 
 const char kContentSuggestionsSubscriptionDataToken[] =
     "ntp_suggestions.content_suggestions_subscription_data.token";
 
+const char kContentSuggestionsGCMSubscriptionTokenCache[] =
+    "ntp_suggestions.content_suggestions_gcm_subscription_token_cache";
+
 }  // namespace prefs
 }  // namespace ntp_snippets