Add namespace sandbox status to LinuxSandbox::GetStatus.

Add namespace sandbox status to LinuxSandbox::GetStatus.

Also add an extra check that the namespace sandbox is enabled in the zygote.

BUG=312380
TBR=nasko@chromium.org

Committed: https://crrev.com/c72852c0917f4b4c0b457c41897e79d8c99ab209
Cr-Commit-Position: refs/heads/master@{#315910}

[rickyz (no longer on Chrome), 2015-02-12 01:04:41]

rickyz@chromium.org changed reviewers:
+ jln@chromium.org

[rickyz (no longer on Chrome), 2015-02-12 01:04:41]

Splitting this out of the sandbox about page change as you suggested.

[jln (very slow on Chromium), 2015-02-12 01:17:57]

lgtm

Do you want to merge the CHECK that checks that GetStatus() is consistent with
the situation with this change?

[rickyz (no longer on Chrome), 2015-02-12 01:19:55]

New patchsets have been uploaded after l-g-t-m from jln@chromium.org

[rickyz (no longer on Chrome), 2015-02-12 01:21:16]

On 2015/02/12 01:17:57, jln wrote:
> lgtm
> 
> Do you want to merge the CHECK that checks that GetStatus() is consistent with
> the situation with this change?

Oops, no idea why I didn't think of that, thanks!

TBRing nasko@ for content/public/common as discussed.

[jln (very slow on Chromium), 2015-02-12 01:21:30]

PS2 lgtm, but update the commit message.

[rickyz (no longer on Chrome), 2015-02-12 01:22:16]

rickyz@chromium.org changed reviewers:
+ nasko@chromium.org

[rickyz (no longer on Chrome), 2015-02-12 01:23:03]

The CQ bit was checked by rickyz@chromium.org

[commit-bot: I haz the power, 2015-02-12 01:24:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/915243002/20001

[commit-bot: I haz the power, 2015-02-12 02:13:44]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-12 02:14:46]

Patchset 2 (id:??) landed as
https://crrev.com/c72852c0917f4b4c0b457c41897e79d8c99ab209
Cr-Commit-Position: refs/heads/master@{#315910}