Finalize backend for fetching more NTPSnippets.

components/ntp_snippets/content_suggestions_service.cc

Index: components/ntp_snippets/content_suggestions_service.cc
diff --git a/components/ntp_snippets/content_suggestions_service.cc b/components/ntp_snippets/content_suggestions_service.cc
index 614854a2afadf0817f14c86ad310fa0c640c3644..0251baaee15f753c3b32db54e5b5c8215bfcb128 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -196,13 +196,15 @@ void ContentSuggestionsService::RegisterProvider(
   providers_.push_back(std::move(provider));
 }
 
-void ContentSuggestionsService::FetchMore(const Category& category,
-                                          const FetchedMoreCallback& callback) {
+void ContentSuggestionsService::Fetch(
+    const Category& category,
+    std::set<std::string> known_suggestion_ids,
+    const FetchingCallback& callback) {
   auto providers_it = providers_by_category_.find(category);
   if (providers_it == providers_by_category_.end())
     return;
 
-  providers_it->second->FetchMore(category, callback);
+  providers_it->second->Fetch(category, known_suggestion_ids, callback);
 }
 
 ////////////////////////////////////////////////////////////////////////////////