[MacViews] Implement ChromeNativeAppWindowViewsMac::FlashFrame.

chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.mm

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.h"
 
 #include "chrome/browser/apps/app_shim/extension_app_shim_handler_mac.h"
 #include "chrome/browser/ui/views/apps/app_window_native_widget_mac.h"
 #include "chrome/browser/ui/views/apps/native_app_window_frame_view_mac.h"
 
@@ skipping 32 matching lines @@
   ChromeNativeAppWindowViews::Show();
 }
 
 void ChromeNativeAppWindowViewsMac::ShowInactive() {
   if (is_hidden_with_app_)
     return;
 
   ChromeNativeAppWindowViews::ShowInactive();
 }
 
+void ChromeNativeAppWindowViewsMac::FlashFrame(bool flash) {
+  apps::ExtensionAppShimHandler::RequestUserAttentionForWindow(
+      app_window(), flash ? apps::APP_SHIM_ATTENTION_CRITICAL
+                          : apps::APP_SHIM_ATTENTION_CANCEL);
+}
+
 void ChromeNativeAppWindowViewsMac::ShowWithApp() {
   is_hidden_with_app_ = false;
   if (!app_window()->is_hidden())
     ShowInactive();
 }
 
 void ChromeNativeAppWindowViewsMac::HideWithApp() {
   is_hidden_with_app_ = true;
   ChromeNativeAppWindowViews::Hide();
 }