Adds a first-run balloon to the Windows notification center.

chrome/browser/status_icons/status_icon_observer.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 CHROME_BROWSER_STATUS_ICONS_STATUS_ICON_OBSERVER_H_
 #define CHROME_BROWSER_STATUS_ICONS_STATUS_ICON_OBSERVER_H_
 
 class StatusIconObserver {
  public:
   // Called when the user clicks on the system tray icon. Clicks that result
   // in the context menu being displayed will not be passed to this observer
   // (i.e. if there's a context menu set on this status icon, and the user
   // right clicks on the icon to display the context menu, OnStatusIconClicked()
   // will not be called).
   // Note: Chrome OS displays the context menu on left button clicks.
   // This will only be fired for this platform if no context menu is present.
   virtual void OnStatusIconClicked() = 0;
 
+#if defined(OS_WIN)
+  // Called when the user clicks on a balloon generated for a system tray icon.
+  // TODO(dewittj): Implement on platforms other than Windows.  Currently this
+  // event will never fire on non-Windows platforms.
+  virtual void OnBalloonClicked() {}
+#endif
+
  protected:
   virtual ~StatusIconObserver() {}
 };
 
 #endif  // CHROME_BROWSER_STATUS_ICONS_STATUS_ICON_OBSERVER_H_