[Android] Upstream remaining changes to NTP UI code.

chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h

Index: chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h
diff --git a/chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h b/chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h
index 65ee309fc6d273295ee1080e0fdc8562c6b01038..3808efc9f250945103d93fadd661e4ef19edfd73 100644
--- a/chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h
+++ b/chrome/browser/ui/webui/ntp/recently_closed_tabs_handler.h
@@ -29,6 +29,9 @@ class RecentlyClosedTabsHandler : public content::WebUIMessageHandler,
   // Callback for the "getRecentlyClosedTabs" message.
   void HandleGetRecentlyClosedTabs(const ListValue* args);
 
+  // Callback for the "clearRecentlyClosed" message.
+  void HandleClearRecentlyClosed(const ListValue* args);
+
   // Observer callback for TabRestoreServiceObserver. Sends data on
   // recently closed tabs to the javascript side of this page to
   // display to the user.
@@ -45,6 +48,10 @@ class RecentlyClosedTabsHandler : public content::WebUIMessageHandler,
       base::ListValue* entry_list_value);
 
  private:
+  // Construct and initialize tab_restore_service_ if it's NULL.
+  // tab_restore_service_ may still be NULL, however, in incognito mode.
+  void EnsureTabRestoreService();
+
   // TabRestoreService that we are observing.
   TabRestoreService* tab_restore_service_;