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

components/ntp_snippets/pref_names.cc

Index: components/ntp_snippets/pref_names.cc
diff --git a/components/ntp_snippets/pref_names.cc b/components/ntp_snippets/pref_names.cc
index 94142761e31ddd97de58b544780b7b72693fd0d5..13a2b61563eee5c5b3cd31de1a8d68bfea96f279 100644
--- a/components/ntp_snippets/pref_names.cc
+++ b/components/ntp_snippets/pref_names.cc
@@ -84,5 +84,8 @@ const char kClickBasedCategoryRankerLastDecayTime[] =
 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