Show no-notification message in the bottom label of message center

ui/message_center/views/message_center_button_bar.cc

 // Copyright 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/views/message_center_button_bar.h"
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "ui/base/models/simple_menu_model.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 260 matching lines @@
   return close_all_button_;
 }
 
 void MessageCenterButtonBar::SetBackArrowVisible(bool visible) {
   if (title_arrow_)
     title_arrow_->SetVisible(visible);
   ViewVisibilityChanged();
   Layout();
 }
 
+void MessageCenterButtonBar::SetTitle(const base::string16& title) {
+  notification_label_->SetText(title);
+}
+
 void MessageCenterButtonBar::ChildVisibilityChanged(views::View* child) {
   InvalidateLayout();
 }
 
 void MessageCenterButtonBar::ButtonPressed(views::Button* sender,
                                            const ui::Event& event) {
   if (sender == close_all_button_) {
     message_center_view()->ClearAllClosableNotifications();
   } else if (sender == settings_button_ || sender == title_arrow_) {
     MessageCenterView* center_view = message_center_view();
     center_view->SetSettingsVisible(!center_view->settings_visible());
   } else if (sender == quiet_mode_button_) {
     if (message_center()->IsQuietMode())
       message_center()->SetQuietMode(false);
     else
       message_center()->EnterQuietModeWithExpire(base::TimeDelta::FromDays(1));
     quiet_mode_button_->SetToggled(message_center()->IsQuietMode());
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
   } else if (sender == close_bubble_button_) {
     message_center_view()->tray()->HideMessageCenterBubble();
 #endif
   } else {
     NOTREACHED();
   }
 }
 
 }  // namespace message_center