Rename Repaint to Paint Invalidation Part 2

This CL refactors the FrameView methods to be paintInvalidation instead
of repaint.

I have left the repaint rect output to be 'repaint' for now as that
seems like a large and scary rebaseline when it lands.

I also did not change the slowRepaints methods as they were previously
mentioned as not having to do with paint invalidation.

BUG=338691

Review URL: https://codereview.chromium.org/306413002

git-svn-id: svn://svn.chromium.org/blink/trunk@175492 bbb929c8-8fbe-4397-9dbb-9b2b20218538