Adding lowbox condition to IsTokenCacheable function.

Adding lowbox condition to IsTokenCacheable function.
Problem discovered during PPAPI out of process tests, where it launches multiple processes with different delegates.

BUG=455496
R=rvargas,cpu,jschuh

Committed: https://crrev.com/5cf7b07fc4fffa4d440761094a015bcebe8f7693
Cr-Commit-Position: refs/heads/master@{#319194}

[jschuh, 2015-03-04 23:45:28]

lgtm, but update the comment to mention app container or lowbox token.

[Shrikant Kelkar, 2015-03-05 00:46:58]

On 2015/03/04 23:45:28, jschuh wrote:
> lgtm, but update the comment to mention app container or lowbox token.

done.

[Shrikant Kelkar, 2015-03-05 00:47:03]

The CQ bit was checked by shrikant@chromium.org

[Shrikant Kelkar, 2015-03-05 00:47:04]

The patchset sent to the CQ was uploaded after l-g-t-m from jschuh@chromium.org
Link to the patchset: https://codereview.chromium.org/977193002/#ps20001 (title:
"Modified comment.")

[commit-bot: I haz the power, 2015-03-05 00:48:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/977193002/20001

[cpu_(ooo_6.6-7.5), 2015-03-05 00:55:30]

lgtm

[commit-bot: I haz the power, 2015-03-05 02:11:23]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-05 02:12:11]

Patchset 2 (id:??) landed as
https://crrev.com/5cf7b07fc4fffa4d440761094a015bcebe8f7693
Cr-Commit-Position: refs/heads/master@{#319194}