Please also check on the easing type Josh asked for (cubic ease in + out).  I'm not sure if native supports that today or not.

That's covered in  issue 691610 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c74bd60acf193d5ef22e4caeb9c8b63bb6d2d46d

commit c74bd60acf193d5ef22e4caeb9c8b63bb6d2d46d
Author: tiborg <tiborg@chromium.org>
Date: Wed Feb 22 16:41:44 2017

Can more conveniently set easing from JS.

- Adds setEasing to Aninmation class.
- Adds classes to instantiate easings with the appropriate parameters.

BUG= 691604 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2696273002
Cr-Commit-Position: refs/heads/master@{#452082}

[modify] https://crrev.com/c74bd60acf193d5ef22e4caeb9c8b63bb6d2d46d/chrome/browser/resources/vr_shell/vr_shell_ui_api.js