CSP: Move 'worker-src' onto 'script-src'

Based on the discussion in https://github.com/w3c/webappsec-csp/issues/146,
we're deprecating 'child-src' and moving 'worker-src' onto 'script-src'.

Intent to Ship: https://groups.google.com/a/chromium.org/d/msg/blink-dev/npKDoKVOUAs/ogtlIFmLBAAJ

BUG=662930,694525

Review-Url: https://codereview.chromium.org/2533313002
Cr-Commit-Position: refs/heads/master@{#458026}
40 files changed