Adding milestone so it doesn't slip off our radar.

This seems to be arguing for the opposite of  bug 716647  -- can you clarify what the intended behavior is?

window.rAF should fire only when the page is visible.  issue 716647  tracks adding a test to ensure that it's fired on desktop, but not on Android (because on desktop the page is still visible, while on Android it isn't).

I think I know what the problem is, and I think it should be fixed with the fallback UI path.

Pretty sure this is fixed. Please re-open if it isn't.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/330651dccd5c85400655080c564a2d3aba8e57f0

commit 330651dccd5c85400655080c564a2d3aba8e57f0
Author: bsheedy <bsheedy@chromium.org>
Date: Tue Jan 16 19:32:11 2018

Enable VR window.rAF test in all activities

Enables WebVrTransitionTest#testWindowRafStopsFiringWhilePresenting in
all activity types that support VR since the bug that was causing it to
fail in CustomTabActivity/WebappActivity has been fixed.

Bug:  793857 
Change-Id: Icd463507366853b5e929d548ef03aa4371f7e057
Reviewed-on: https://chromium-review.googlesource.com/868452
Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529488}
[modify] https://crrev.com/330651dccd5c85400655080c564a2d3aba8e57f0/chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/WebVrTransitionTest.java