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

chrome/browser/status_icons/status_icon_observer.h

Index: chrome/browser/status_icons/status_icon_observer.h
diff --git a/chrome/browser/status_icons/status_icon_observer.h b/chrome/browser/status_icons/status_icon_observer.h
index 28ee3d85fb6efa429dee05d5252e8641277b96d6..418356715c690d8ae15200b4374bd0ee398cd417 100644
--- a/chrome/browser/status_icons/status_icon_observer.h
+++ b/chrome/browser/status_icons/status_icon_observer.h
@@ -16,6 +16,13 @@ class StatusIconObserver {
   // 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() {}
 };