QA: Random stab in dark to get chrome tests to pass

I wonder if browser width / height includes browser chrome - thus
it's possible the window.innerWidth / window.innerHeight is slightly
less when padding is introduced.

Make both numbers significantly greater than 768px to account for error
margin.

Change-Id: Icfd1fec741995dc84fca2001e6dac5b4c382e9d5
Merge "QA: Random stab in dark to get chrome tests to pass"