[ServiceWorker] Introduce the directory restriction of ServiceWorker scope [3/3 blink]

[ServiceWorker] Introduce the directory restriction of ServiceWorker scope [3/3 blink]

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


[1/3 blink] https://codereview.chromium.org/674133004/
 Update LayoutTests to be subject to the directory restrictions.
[2/3 chromium] https://codereview.chromium.org/677003002/
 Introduce this restriction in Chromium side.
[3/3 blink] This patch
 Introduce this restriction in Blink side and update LayoutTest.

BUG=423983

[horo, 2014-10-25 01:39:15]

horo@chromium.org changed reviewers:
+ falken@chromium.org

[horo, 2014-10-25 01:39:16]

falken@
Could you please review this?
https://codereview.chromium.org/672383003/ was reverted because of the chromium
side test break.

[horo, 2014-10-26 04:00:13]

I'll close this cl.
I changed the way to re-introduce the scope restriction.