[S.P.] Move clip painting to SVGClipPainter.

BUG=462077

Review URL: https://codereview.chromium.org/979883002

git-svn-id: svn://svn.chromium.org/blink/trunk@191430 bbb929c8-8fbe-4397-9dbb-9b2b20218538
8 files changed