Fix //third_party/cec to not disable -Wunused-function.

ash/system/web_notification/web_notification_tray_unittest.cc

Index: ash/system/web_notification/web_notification_tray_unittest.cc
diff --git a/ash/system/web_notification/web_notification_tray_unittest.cc b/ash/system/web_notification/web_notification_tray_unittest.cc
index 783b8b22bced0a1e268c217cfd3a50b85e567435..92928e4307d873e0ebf352866b288b1dc4e77503 100644
--- a/ash/system/web_notification/web_notification_tray_unittest.cc
+++ b/ash/system/web_notification/web_notification_tray_unittest.cc
@@ -54,6 +54,8 @@ WebNotificationTray* GetTray() {
       ->web_notification_tray();
 }
 
+#if defined(OS_CHROMEOS)
+
 WebNotificationTray* GetSecondaryTray() {
   StatusAreaWidget* status_area_widget =
       StatusAreaWidgetTestHelper::GetSecondaryStatusAreaWidget();
@@ -62,6 +64,8 @@ WebNotificationTray* GetSecondaryTray() {
   return NULL;
 }
 
+#endif
+
 message_center::MessageCenter* GetMessageCenter() {
   return GetTray()->message_center();
 }