Update Mac notification tray behavior.

ui/message_center/notification.cc

 // 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.
 
 #include "ui/message_center/notification.h"
 
 #include "base/logging.h"
 #include "ui/message_center/notification_types.h"
 
 namespace {
@@ skipping 41 matching lines @@
                            NotificationDelegate* delegate)
     : type_(type),
       id_(id),
       title_(title),
       message_(message),
       icon_(icon),
       display_source_(display_source),
       extension_id_(extension_id),
       serial_number_(g_next_serial_number_++),
       optional_fields_(optional_fields),
+      shown_as_popup_(false),
+      is_read_(false),
+      is_expanded_(false),
       delegate_(delegate) {}
 
 Notification::Notification(const Notification& other)
     : type_(other.type_),
       id_(other.id_),
       title_(other.title_),
       message_(other.message_),
       icon_(other.icon_),
       display_source_(other.display_source_),
       extension_id_(other.extension_id_),
@@ skipping 38 matching lines @@
     return;
   optional_fields_.buttons[index].icon = icon;
 }
 
 void Notification::SetSystemPriority() {
   optional_fields_.priority = SYSTEM_PRIORITY;
   optional_fields_.never_timeout = true;
 }
 
 }  // namespace message_center