Implement progress bar spec (determinate and indeterminate).

chrome/browser/download/notification/download_item_notification.cc

Index: chrome/browser/download/notification/download_item_notification.cc
diff --git a/chrome/browser/download/notification/download_item_notification.cc b/chrome/browser/download/notification/download_item_notification.cc
index 095d3460c5445c701c74503a9850f67cb3d99ee5..dfaed46448c630dbcdad2e2281808645004a462b 100644
--- a/chrome/browser/download/notification/download_item_notification.cc
+++ b/chrome/browser/download/notification/download_item_notification.cc
@@ -387,6 +387,7 @@ void DownloadItemNotification::UpdateNotificationData(
           // Negative progress value shows an indeterminate progress bar.
           notification_->set_progress(-1);
         }
+
         notification_->set_type(message_center::NOTIFICATION_TYPE_PROGRESS);
         break;
       }