win: Shard core_html target.

BUG=352495
TBR=jamesr@chromium.org

Review URL: https://codereview.chromium.org/198003009

git-svn-id: svn://svn.chromium.org/blink/trunk@169209 bbb929c8-8fbe-4397-9dbb-9b2b20218538