Google forked Blink because how Apple and Google saw the future of browsers drastically differed. I'm going to venture a guess that Microsoft selected Chromium because their vision is closer to Google's than either Firefox or Webkit.
> Google forked Blink because how Apple and Google saw the future of browsers drastically differed.
That's not accurate. Google forked Blink for many reasons (WebKit2, dev tools policies, etc.) that collectively added up to a dysfunctional relationship.
But on the other hand, Google forked Blink away from Webkit specifically so it wouldn't have to share control of the codebase with Apple.
Do you think Google is willing to share control over Blink with Microsoft?