Implement time stamp in new-style notification.

ui/message_center/views/notification_view_md.cc

 // Copyright 2017 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/notification_view_md.h"
 
 #include <stddef.h>
 
 #include "base/strings/string_util.h"
 #include "ui/base/cursor/cursor.h"
@@ skipping 449 matching lines @@
 }
 
 void NotificationViewMD::RequestFocusOnCloseButton() {
   if (header_row_->IsCloseButtonEnabled())
     header_row_->close_button()->RequestFocus();
 }
 
 void NotificationViewMD::CreateOrUpdateContextTitleView(
     const Notification& notification) {
   header_row_->SetAppName(notification.display_source());
+  header_row_->SetTimestamp(notification.timestamp());
 }
 
 void NotificationViewMD::CreateOrUpdateTitleView(
     const Notification& notification) {
   if (notification.type() == NOTIFICATION_TYPE_PROGRESS) {
     left_content_->RemoveChildView(title_view_);
     title_view_ = nullptr;
     return;
   }
   const gfx::FontList& font_list = views::Label().font_list().Derive(
@@ skipping 287 matching lines @@
                                   header_row_->expand_button()->HasFocus()) ||
                                  (header_row_->IsCloseButtonEnabled() &&
                                   header_row_->close_button()->HasFocus()) ||
                                  (header_row_->IsSettingsButtonEnabled() &&
                                   header_row_->settings_button()->HasFocus());
 
   header_row_->SetControlButtonsVisible(target_visibility);
 }
 
 }  // namespace message_center