Delete DeprecatedDirtyCompositingDuringCompositingUpdate

This CL is a bit of a parlor trick, but it seems worthwhile to remove
DeprecatedDirtyCompositingDuringCompositingUpdate.

Review URL: https://codereview.chromium.org/334443005

git-svn-id: svn://svn.chromium.org/blink/trunk@175977 bbb929c8-8fbe-4397-9dbb-9b2b20218538