It will be very helpful. Thanks!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b67034891a2338982544a9c524ef1394803f985d

commit b67034891a2338982544a9c524ef1394803f985d
Author: Becca Hughes <beccahughes@chromium.org>
Date: Tue May 01 19:23:29 2018

Media Engagement: Add flags and version to WebUI

Add flag states and preload version to chrome://media-engagement
to make it easier to diagnose bugs in MEI.

BUG= 835938 

Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I736f17f5b020b459c236abdabd9d0961efea29d3
Reviewed-on: https://chromium-review.googlesource.com/1024805
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#555138}
[modify] https://crrev.com/b67034891a2338982544a9c524ef1394803f985d/chrome/browser/media/media_engagement_score_details.mojom
[modify] https://crrev.com/b67034891a2338982544a9c524ef1394803f985d/chrome/browser/resources/media/media_engagement.js
[modify] https://crrev.com/b67034891a2338982544a9c524ef1394803f985d/chrome/browser/ui/webui/media/media_engagement_ui.cc