[ServiceWorker] Add m_skipServiceWorker to CrossThreadResourceRequestData.

I added m_skipServiceWorker to ResourceRequest in https://codereview.chromium.org/527703002/.
But I forgot to add it to CrossThreadResourceRequestData.

BUG=402093
TEST=none

Review URL: https://codereview.chromium.org/547563002

git-svn-id: svn://svn.chromium.org/blink/trunk@181531 bbb929c8-8fbe-4397-9dbb-9b2b20218538