Browser side support (sans UI) for desktop notifications....

chrome/browser/notifications/notification_object_proxy.h

+// Copyright (c) 2009 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 CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_OBJECT_PROXY_H_
+#define CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_OBJECT_PROXY_H_
+
+#include "base/ref_counted.h"
+
+class MessageLoop;
+namespace IPC {
+class Message;
+}
+
+// A NotificationObjectProxy stands in for the JavaScript Notification object
+// which corresponds to a notification toast on the desktop.  It can be signaled
+// when various events occur regarding the desktop notification, and the
+// attached JS listeners will be invoked in the renderer or worker process.
+class NotificationObjectProxy :
+    public base::RefCountedThreadSafe<NotificationObjectProxy> {
+ public:
+  // Creates a Proxy object with the necessary callback information.
+  NotificationObjectProxy(int process_id, int route_id,
+                          int notification_id, bool worker);
+
+  // To be called when the desktop notification is actually shown.
+  void Display();
+
+  // To be called when the desktop notification cannot be shown due to an
+  // error.
+  void Error();
+
+  // To be called when the desktop notification is closed.  If closed by a
+  // user explicitly (as opposed to timeout), |by_user| should be true.
+  void Close(bool by_user);
+
+ private:
+  // Called on UI thread to schedule a message for sending.
+  void DeliverMessage(IPC::Message* message);
+
+  // Called via Task on IO thread to actually send a message to a notification.
+  void Send(IPC::Message* message);
+
+  // Callback information to find the JS Notification object where it lives.
+  int process_id_;
+  int route_id_;
+  int notification_id_;
+  bool worker_;
+};
+
+#endif  // CHROME_BROWSER_NOTIFICATIONS_NOTIFICATION_OBJECT_PROXY_H_