Re-factor system tray code controlling launcher visibility

ash/system/web_notification/web_notification_tray.h

Index: ash/system/web_notification/web_notification_tray.h
diff --git a/ash/system/web_notification/web_notification_tray.h b/ash/system/web_notification/web_notification_tray.h
index 726f78781592ffd29c70d9e9bf919fc8b5c7c87b..37c3e62ee62b9bb65d15a0a563896f2811d308c3 100644
--- a/ash/system/web_notification/web_notification_tray.h
+++ b/ash/system/web_notification/web_notification_tray.h
@@ -116,6 +116,12 @@ class ASH_EXPORT WebNotificationTray : public internal::TrayBackgroundView {
   // Updates tray visibility login status of the system changes.
   void UpdateAfterLoginStatusChange(user::LoginStatus login_status);
 
+  // Returns true if the message center bubble is visible.
+  bool IsMessageCenterBubbleVisible() const;
+
+  // Returns true if the mouse is inside the notification bubble.
+  bool IsMouseInNotificationBubble() const;
+
   // Overridden from TrayBackgroundView.
   virtual void SetShelfAlignment(ShelfAlignment alignment) OVERRIDE;
   virtual void AnchorUpdated() OVERRIDE;