Correctly remove file browser notifications from Ash notification tray.

chrome/browser/background/background_contents_service.cc

Index: chrome/browser/background/background_contents_service.cc
diff --git a/chrome/browser/background/background_contents_service.cc b/chrome/browser/background/background_contents_service.cc
index 8726ebeb682cb287bba1271ed49b61db2800ac58..9ff318e540ba7d92cc5cd2c1097ecda7baa22744 100644
--- a/chrome/browser/background/background_contents_service.cc
+++ b/chrome/browser/background/background_contents_service.cc
@@ -118,7 +118,7 @@ void ShowBalloon(const Extension* extension, Profile* profile) {
   GURL icon_url(extension->GetIconURL(ExtensionIconSet::EXTENSION_ICON_SMALLISH,
                                       ExtensionIconSet::MATCH_BIGGER));
   DesktopNotificationService::AddNotification(
-      extension->url(), title, message, icon_url,
+      extension->url(), title, message, icon_url, string16(),
       new CrashNotificationDelegate(profile, extension), profile);
 #endif
 }