Adds a Fetch() method to the ContentSuggestionService which asks any provider to provide more conte…

components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc

Index: components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
diff --git a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
index c495c07b285c1d9d1fa8e8a051e59facf07c3b94..58f5f10f87edc75076672fb2c696273bdac9eab7 100644
--- a/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
+++ b/components/ntp_snippets/offline_pages/recent_tab_suggestions_provider.cc
@@ -101,6 +101,16 @@ void RecentTabSuggestionsProvider::FetchSuggestionImage(
       FROM_HERE, base::Bind(callback, gfx::Image()));
 }
 
+void RecentTabSuggestionsProvider::Fetch(
+    const Category& category,
+    const std::set<std::string>& known_suggestion_ids,
+    FetchingCallback callback) {
+  NOTREACHED();
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, base::Passed(std::vector<ContentSuggestion>())));
+}
+
 void RecentTabSuggestionsProvider::ClearHistory(
     base::Time begin,
     base::Time end,