Implement notifications for the DisplayBalloon method on Linux and Mac.

chrome/browser/ui/gtk/status_icons/status_icon_gtk.h

 // Copyright (c) 2011 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_UI_GTK_STATUS_ICONS_STATUS_ICON_GTK_H_
 #define CHROME_BROWSER_UI_GTK_STATUS_ICONS_STATUS_ICON_GTK_H_
 #pragma once
 
 #include <gtk/gtk.h>
 
 #include "base/compiler_specific.h"
+#include "chrome/browser/status_icons/desktop_notification_balloon.h"
 #include "chrome/browser/status_icons/status_icon.h"
 #include "ui/base/gtk/gtk_signal.h"
 
 class MenuGtk;
 class SkBitmap;
 
 class StatusIconGtk : public StatusIcon {
  public:
   StatusIconGtk();
   virtual ~StatusIconGtk();
 
   // Overridden from StatusIcon:
   virtual void SetImage(const SkBitmap& image) OVERRIDE;
   virtual void SetPressedImage(const SkBitmap& image) OVERRIDE;
   virtual void SetToolTip(const string16& tool_tip) OVERRIDE;
   virtual void DisplayBalloon(const SkBitmap& icon,
                               const string16& title,
-                              const string16& contents);
+                              const string16& contents) OVERRIDE;
 
   // Exposed for testing.
   CHROMEGTK_CALLBACK_0(StatusIconGtk, void, OnClick);
 
  protected:
   // Overridden from StatusIcon.
   virtual void UpdatePlatformContextMenu(ui::MenuModel* menu);
 
  private:
   // Callback invoked when user right-clicks on the status icon.
   CHROMEGTK_CALLBACK_2(StatusIconGtk, void, OnPopupMenu, guint, guint);
 
   // The currently-displayed icon for the window.
   GtkStatusIcon* icon_;
 
   // The context menu for this icon (if any).
   scoped_ptr<MenuGtk> menu_;
 
+  // Notification balloon.
+  DesktopNotificationBalloon notification_;
+
   DISALLOW_COPY_AND_ASSIGN(StatusIconGtk);
 };
 
 #endif  // CHROME_BROWSER_UI_GTK_STATUS_ICONS_STATUS_ICON_GTK_H_