RemoteContentSuggestions: Stores the time of the last successful background fetch in a pref

components/ntp_snippets/remote/remote_suggestions_provider.h

Index: components/ntp_snippets/remote/remote_suggestions_provider.h
diff --git a/components/ntp_snippets/remote/remote_suggestions_provider.h b/components/ntp_snippets/remote/remote_suggestions_provider.h
index a8081b7ee9ffdadb3b853164edd1d175b786d2c6..ca68856cfde2bf77d9f30e8cc6aa4367dab730fe 100644
--- a/components/ntp_snippets/remote/remote_suggestions_provider.h
+++ b/components/ntp_snippets/remote/remote_suggestions_provider.h
@@ -151,6 +151,11 @@ class RemoteSuggestionsProvider final
     return category_contents_.find(category)->second.dismissed;
   }
 
+  // Overrides internal clock for testing purposes.
+  void SetTickClockForTesting(std::unique_ptr<base::TickClock> tick_clock) {
+    tick_clock_ = std::move(tick_clock);
+  }
+
  private:
   friend class RemoteSuggestionsProviderTest;
 
@@ -261,11 +266,14 @@ class RemoteSuggestionsProvider final
   // Callback for fetch-more requests with the NTPSnippetsFetcher.
   void OnFetchMoreFinished(
       const FetchDoneCallback& fetching_callback,
-      NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories);
+      NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories,
+      NTPSnippetsFetcher::FetchResult fetch_result);
 
   // Callback for regular fetch requests with the NTPSnippetsFetcher.
   void OnFetchFinished(
-      NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories);
+      bool interactive_request,
+      NTPSnippetsFetcher::OptionalFetchedCategories fetched_categories,
+      NTPSnippetsFetcher::FetchResult fetch_status);
 
   // Moves all snippets from |to_archive| into the archive of the |content|.
   // Clears |to_archive|. As the archive is a FIFO buffer of limited size, this
@@ -407,6 +415,9 @@ class RemoteSuggestionsProvider final
   // Request throttler for limiting requests to thumbnail images.
   RequestThrottler thumbnail_requests_throttler_;
 
+  // A clock for getting the time. This allows to inject a tick clock in tests.
+  std::unique_ptr<base::TickClock> tick_clock_;
+
   DISALLOW_COPY_AND_ASSIGN(RemoteSuggestionsProvider);
 };