Add percentage of progress in notification header.

ui/message_center/views/notification_view_md.cc

Index: ui/message_center/views/notification_view_md.cc
diff --git a/ui/message_center/views/notification_view_md.cc b/ui/message_center/views/notification_view_md.cc
index 66e70fd5d2a6b06926314a4a680dc5d7b419b8d9..2cb5d8b5bf71dd0e97069bb780f52b17889f5360 100644
--- a/ui/message_center/views/notification_view_md.cc
+++ b/ui/message_center/views/notification_view_md.cc
@@ -551,6 +551,7 @@ void NotificationViewMD::CreateOrUpdateProgressBarView(
   if (notification.type() != NOTIFICATION_TYPE_PROGRESS) {
     left_content_->RemoveChildView(progress_bar_view_);
     progress_bar_view_ = nullptr;
+    header_row_->ClearProgress();
     return;
   }
 
@@ -566,6 +567,8 @@ void NotificationViewMD::CreateOrUpdateProgressBarView(
 
   progress_bar_view_->SetValue(notification.progress() / 100.0);
   progress_bar_view_->SetVisible(notification.items().empty());
+
+  header_row_->SetProgress(notification.progress());
 }
 
 void NotificationViewMD::CreateOrUpdateListItemViews(