[Mac] Bounce app shims when app windows request attention.

apps/app_shim/extension_app_shim_handler_mac.h

Index: apps/app_shim/extension_app_shim_handler_mac.h
diff --git a/apps/app_shim/extension_app_shim_handler_mac.h b/apps/app_shim/extension_app_shim_handler_mac.h
index 0f7ae0c37195f83ca777747bbb42acf5fddfb302..bc8efb14c077c65e57f59f83468fd2b44de807b7 100644
--- a/apps/app_shim/extension_app_shim_handler_mac.h
+++ b/apps/app_shim/extension_app_shim_handler_mac.h
@@ -80,8 +80,14 @@ class ExtensionAppShimHandler : public AppShimHandler,
   static void FocusAppForWindow(AppWindow* app_window);
 
   // Brings the window to the front without showing it and instructs the shim to
-  // request user attention. Returns false if there is no shim for this window.
-  static bool RequestUserAttentionForWindow(AppWindow* app_window);
+  // request user attention. If there is no shim, show the app and return false.
+  static bool ActivateAndRequestUserAttentionForWindow(AppWindow* app_window);
+
+  // Instructs the shim to request user attention. Returns false if there is no
+  // shim for this window.
+  static void RequestUserAttentionForWindow(
+      AppWindow* app_window,
+      AppShimAttentionType attention_type);
 
   // Called by AppControllerMac when Chrome hides.
   static void OnChromeWillHide();