Chrome Version:n/a
Chrome OS Version: ToT
Chrome OS Platform: n/a
<b>Network info: <network, encryption type, router model (if known)></b>

Please specify Cr-* of the system to which this bug/feature applies (add
the label below).

Steps To Reproduce:
(1) run power_LoadTest.fast


Expected Result:
background window with 5 tabs is always in the background.

Actual Result:
Sometimes the window is seen in front of the foreground tab.

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Not sure.  I saw it w/ modified version of this CL, crrev.com/c/1352936 where all pages were 'about:blank'

What is the impact to the user, and is there a workaround? If so, what is
it?
none, its just an autotest

Next step is to see how reproducible it is and understand if there's a way to guarantee it doesn't happen or flag it when it does.