Prevent leaks of cross context maps in the Oracle.

Prevent leaks of cross context maps in the Oracle.

Some code in type-info.cc could allow a cross context map to be visible to
crankshaft. Tighten up this code to be certain that only a JSFunction, an
AllocationSite or a Symbol can be returned.

R=verwaest@chromium.org
BUG=

Committed: https://crrev.com/821655fb5778141140a7d4b0151aede04fca522b
Cr-Commit-Position: refs/heads/master@{#27417}

[mvstanton, 2015-03-24 14:13:21]

Hi Toon, thx for the pointer to this. PTAL,
--Michael

[Toon Verwaest, 2015-03-24 15:07:30]

lgtm

[mvstanton, 2015-03-24 15:08:44]

The CQ bit was checked by mvstanton@chromium.org

[commit-bot: I haz the power, 2015-03-24 15:09:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1026343004/1

[commit-bot: I haz the power, 2015-03-24 15:37:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-24 15:37:32]

Patchset 1 (id:??) landed as
https://crrev.com/821655fb5778141140a7d4b0151aede04fca522b
Cr-Commit-Position: refs/heads/master@{#27417}