Do not hide the web notification popups by the system tray, rather let them avoid (2nd)

ui/message_center/views/message_popup_collection.h

 // Copyright (c) 2013 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 UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_COLLECTION_H_
 #define UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_COLLECTION_H_
 
 #include <list>
 #include <map>
 
@@ skipping 11 matching lines @@
 
 namespace base {
 class RunLoop;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace ash {
+class WebNotificationTrayTest;
 FORWARD_DECLARE_TEST(WebNotificationTrayTest, ManyPopupNotifications);
 }
 
 namespace message_center {
 namespace test {
 class MessagePopupCollectionTest;
 class MessagePopupCollectionWidgetsTest;
 }
 
 class MessageCenter;
@@ skipping 60 matching lines @@
   // Overridden from gfx::DislayObserver:
   virtual void OnDisplayBoundsChanged(const gfx::Display& display) OVERRIDE;
   virtual void OnDisplayAdded(const gfx::Display& new_display) OVERRIDE;
   virtual void OnDisplayRemoved(const gfx::Display& old_display) OVERRIDE;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ash::WebNotificationTrayTest,
                            ManyPopupNotifications);
   friend class test::MessagePopupCollectionTest;
   friend class test::MessagePopupCollectionWidgetsTest;
+  friend class ash::WebNotificationTrayTest;
   typedef std::list<ToastContentsView*> Toasts;
 
   void CloseAllWidgets();
 
   // Returns the x-origin for the given toast bounds in the current work area.
   int GetToastOriginX(const gfx::Rect& toast_bounds);
 
   // Iterates toasts and starts closing the expired ones.
   void CloseToasts();
 
@@ skipping 69 matching lines @@
 
   // True if the first item should not have spacing against the tray.
   bool first_item_has_no_margin_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePopupCollection);
 };
 
 }  // namespace message_center
 
 #endif // UI_MESSAGE_CENTER_VIEWS_MESSAGE_POPUP_COLLECTION_H_