Oops, I somehow assumed this this had been assigned to me as I'm the last to modify the camera code and created https://chromium-review.googlesource.com/c/chromium/src/+/697064 to fix it. I hope I was not duplicating work. Steven, feel free to re-assign this back to you and -1 the patch if you were planning to fix this some other way.

Nope, I try to be good about marking things I am actually working on as 'Started'.

I just didn't want to throw every 'change picture' bug your way, especially ones that predate your changes, but I am more than happy to have you fix this :) Thanks!

Feel free to assign bugs to me if you like. Sometimes it's obvious to me what's wrong as all the changes I've made to this code lately has made me very familiar with it. I'll just mark bugs as available if I don't have time to look at it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/46c814ce7e142ef5b0c998e26b36b425c2495572

commit 46c814ce7e142ef5b0c998e26b36b425c2495572
Author: David Reveman <reveman@chromium.org>
Date: Tue Oct 03 18:45:00 2017

Change Picture: Center and scale camera video correctly.

Camera video preview was assuming 3:2 aspect ratio. This assumption
is wrong on a large range of devices in landscape mode and
completely breaks down in portrait mode where camera output on a
3:2 device becomes 2:3.

This updates the code for the camera preview so the video is always
centered and scaled to cover the preview area.

Bug:  764666 
Test: manual
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I244972106686a07dfc79263b5c2988839093f0ba
Reviewed-on: https://chromium-review.googlesource.com/697064
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#506121}
[modify] https://crrev.com/46c814ce7e142ef5b0c998e26b36b425c2495572/ui/webui/resources/cr_elements/chromeos/cr_picture/cr_camera.html