What needs to be done?  From what I can tell, the roller is doing the right thing, eg. https://chromium-review.googlesource.com/c/chromium/src/+/689174 seems to be using the correct repo.

I believe the roller is still doing the right thing because we have auto mirroring that roll  chromium.googlesource.com/catapult to github. 

So the process look s.t like:
1) Commits go to chromium.googlesource.com/catapult
2) Changes in chromium.googlesource.com/catapult roll to github.com/catapult-project/catapult
3) Changes in github.com/catapult-project/catapult roll to chromium/src through catapult roller

We want to change (3) so that changes chromium.googlesource.com/catapult roll chomium/src directly

FTR the roller doesn't explicitly use the child repo URL (catapult in this case); it syncs the parent repo (src.git), gets the path to the child repo from DEPS, and does a git fetch in that location.  IIRC gclient knows how to switch the upstream when it changes in DEPS, so syncing the parent should fix the child.

I logged in to the VM for this roller to verify, and it seems correct to me, though if you want we could turn off the mirroring to test it:

$ cd /path/to/chromium/src
$ git log -n1
commit 475a3ee1523ac83f68f4ac828f9f44c673a97dc3
Author: Gauthier Ambard <gambard@chromium.org>
Date:   Thu Sep 28 12:00:07 2017 +0000

    Fix "Open History" from Recent Tabs
    
    The completion block to open the history wasn't used in the completion
    block of the dismiss animation of the Recent Tabs.
    This CL fixes it.
    
    Bug:  769022 
    Change-Id: I0a5c73d02903dc68aba47115dea6880c5027ae86
    Reviewed-on: https://chromium-review.googlesource.com/689834
    Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
    Commit-Queue: Gauthier Ambard <gambard@chromium.org>
    Cr-Commit-Position: refs/heads/master@{#504972}
$ cd third_party/catapult
$ git remote -v
origin	https://chromium.googlesource.com/a/catapult.git (fetch)
origin	https://chromium.googlesource.com/a/catapult.git (push)
$ git log -n1
commit 591738408846bcf010452d5fbbc2c229efaa1dcf
Author: John Chen <johnchen@chromium.org>
Date:   Wed Sep 27 16:33:43 2017 -0700

    Finish migrating media metrics to TBMv2
    
    Update media metrics to add buffering time, dropped frame count,
    and seek time.
    
    An example trace that can use these metrics is available at
    http://www/~zhanliang/3020433002.trace.html, with corresponding
    histograms at http://www/~zhanliang/3020433002.html.
    
    Bug:  chromium:700160 
    Change-Id: Iaae2260db02f1b89599ab641bbe8f9503eb23d0b
    Reviewed-on: https://chromium-review.googlesource.com/687831
    Reviewed-by: Ben Hayden <benjhayden@chromium.org>
    Commit-Queue: John Chen <johnchen@chromium.org>

Ah great, thanks for the explanation!