[NTP Snippets] FetchMore backend

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 9d037fa862f137b09324f4c42ed50214a959ea87..614854a2afadf0817f14c86ad310fa0c640c3644 100644
--- a/components/ntp_snippets/content_suggestions_service.cc
+++ b/components/ntp_snippets/content_suggestions_service.cc
@@ -196,6 +196,15 @@ void ContentSuggestionsService::RegisterProvider(
   providers_.push_back(std::move(provider));
 }
 
+void ContentSuggestionsService::FetchMore(const Category& category,
+                                          const FetchedMoreCallback& callback) {
+  auto providers_it = providers_by_category_.find(category);
+  if (providers_it == providers_by_category_.end())
+    return;
+
+  providers_it->second->FetchMore(category, callback);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // Private methods