Avoid subtree style recalc for fullscreen pseudos.

Do not let the presence of any of the following pseudo classes require a
sub-tree style recalc:

:-webkit-full-screen
:-webkit-full-screen-ancestor
:-webkit-full-screen-document

R=chrishtr@chromium.org,esprehn@chromium.org
BUG=425070

Review URL: https://codereview.chromium.org/663023003

git-svn-id: svn://svn.chromium.org/blink/trunk@184441 bbb929c8-8fbe-4397-9dbb-9b2b20218538