Add functionality to the Windows 8 notification display functionality to invoke a caller specified …

base/win/metro.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_WIN_METRO_H_
 #define BASE_WIN_METRO_H_
 
 #include <windows.h>
 #include <wpcapi.h>
 
@@ skipping 66 matching lines @@
 // This function should ideally be called on the UI thread.
 BASE_EXPORT bool IsParentalControlActivityLoggingOn();
 
 // Returns the type of launch and the activation params. For example if the
 // the launch is for METRO_PROTOCOL then the params is a url.
 BASE_EXPORT MetroLaunchType GetMetroLaunchParams(string16* params);
 
 // Handler function for the buttons on a metro dialog box
 typedef void (*MetroDialogButtonPressedHandler)();
 
+// Handler function invoked when a metro style notification is clicked.
+typedef void (*MetroNotificationClickedHandler)(const wchar_t* context);
+
 // Function to display metro style notifications.
 typedef void (*MetroNotification)(const char* origin_url,
                                   const char* icon_url,
                                   const wchar_t* title,
                                   const wchar_t* body,
                                   const wchar_t* display_source,
-                                  const char* notification_id);
-
+                                  const char* notification_id,
+                                  MetroNotificationClickedHandler handler,
+                                  const wchar_t* handler_context);
 
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_WIN_METRO_H_