At least in my part of the googleverse, we have automated tests running in all the browsers (even ie11).
But I'll admit I will also poke around outside of the tests, and I'll usually only be doing that in chrome, unless I've had a bug report about firefox in particular. And I'll only really open up Safari when I'm testing VoiceOver. ChromeVox just isn't good enough.
Oh, I’m sure there are automated tests. But if you have 50,000 developers using Google Docs in Chrome, they’re gonna submit some high-quality bug reports internally, whenever it breaks.
But I'll admit I will also poke around outside of the tests, and I'll usually only be doing that in chrome, unless I've had a bug report about firefox in particular. And I'll only really open up Safari when I'm testing VoiceOver. ChromeVox just isn't good enough.