Ship sandbox changes.

Ship sandbox changes.

This patch enables the two changes specified at [1]: 'allow-modals', and
'allow-popups-to-escape-sandbox'.

Intent to ship: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/wXbgxLu63Fo

[1]: https://wiki.whatwg.org/index.php?title=Iframe_sandbox_improvments

BUG=487157, 483624
R=jochen@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199016

[Mike West, 2015-07-14 22:40:50]

Assuming there's another LGTM on the thread in the morning, WDYT about this CL?

-mike

[jochen (gone - plz use gerrit), 2015-07-15 13:34:59]

there isn't one yet :-/

[jochen (gone - plz use gerrit), 2015-07-15 21:38:36]

lgtm

[Mike West, 2015-07-15 21:47:03]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2015-07-15 21:47:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1238793004/1

[commit-bot: I haz the power, 2015-07-16 02:14:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-16 02:14:50]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/70611)

[Mike West, 2015-07-16 06:52:04]

The CQ bit was checked by mkwst@chromium.org

[commit-bot: I haz the power, 2015-07-16 06:52:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1238793004/1

[commit-bot: I haz the power, 2015-07-16 08:19:10]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199016