Replace Ash web notification tray view with a button.

ash/system/tray/system_tray.cc

 // 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.
 
 #include "ash/system/tray/system_tray.h"
 
 #include "ash/shell.h"
 #include "ash/shell/panel_window.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/audio/tray_volume.h"
@@ skipping 37 matching lines @@
 #include "ui/views/view.h"
 
 namespace ash {
 
 // SystemTray
 
 using internal::SystemTrayBubble;
 using internal::TrayBubbleView;
 
 SystemTray::SystemTray(internal::StatusAreaWidget* status_area_widget)
-    : internal::TrayBackgroundView(status_area_widget),
+    : internal::TrayBackgroundView(status_area_widget, true),
       items_(),
       accessibility_observer_(NULL),
       audio_observer_(NULL),
       bluetooth_observer_(NULL),
       brightness_observer_(NULL),
       caps_lock_observer_(NULL),
       clock_observer_(NULL),
       drive_observer_(NULL),
       ime_observer_(NULL),
       locale_observer_(NULL),
@@ skipping 375 matching lines @@
         ConvertPointToWidget(this, &point);
         arrow_offset = point.x();
       }
     }
     ShowDefaultViewWithOffset(BUBBLE_CREATE_NEW, arrow_offset);
   }
   return true;
 }
 
 }  // namespace ash