Update first download notification correctly if there are multiple notifications

chrome/browser/download/notification/download_item_notification.h

Index: chrome/browser/download/notification/download_item_notification.h
diff --git a/chrome/browser/download/notification/download_item_notification.h b/chrome/browser/download/notification/download_item_notification.h
index 0e9e13268cc45e9f3834272077df4e4f915c4d39..0506235ae7db9e357a1777fbae37c62b791ae2b1 100644
--- a/chrome/browser/download/notification/download_item_notification.h
+++ b/chrome/browser/download/notification/download_item_notification.h
@@ -105,8 +105,6 @@ class DownloadItemNotification : public DownloadNotification,
   // Flag to show the notification on next update. If true, the notification
   // goes visible. The initial value is true so it gets shown on initial update.
   bool show_next_ = true;
-  // Current vilibility status of the notification.
-  bool visible_ = false;
 
   int image_resource_id_ = 0;
   std::pair<gfx::VectorIconId, SkColor> vector_icon_params_;
@@ -120,6 +118,12 @@ class DownloadItemNotification : public DownloadNotification,
   // Status of the preview image decode.
   ImageDecodeStatus image_decode_status_ = NOT_STARTED;
 
+  // Pointer to the message center instance.
+  message_center::MessageCenter* message_center_;
+
+  void SetMessageCenterForTest(
+      message_center::MessageCenter* message_center);
+
   base::WeakPtrFactory<DownloadItemNotification> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemNotification);