Introduce the directory restriction of ServiceWorker scope in chromium side.

This restriction doesn't allow registration of the ServiceWorker scope outside the script directory.
As per discussion on https://github.com/slightlyoff/ServiceWorker/issues/468

BUG=423983

Review URL: https://codereview.chromium.org/677003002

Cr-Commit-Position: refs/heads/master@{#301547}
2 files changed