Zygote: small cleanup

Zygote: small cleanup

- Add a few NOTREACHED() where appropriate.
- Create a new GetProcessInfo() helper to use the process_info_map_.
- Get rid of a rarely used code path after fork().

BUG=276747
R=mseaborn@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=218806

[jln (very slow on Chromium), 2013-08-21 02:18:27]

Mark, as discussed, here's a follow-up small cleanup.

I didn't put much effort in figuring out whether the new DCHECK() / NOTREACHED()
will trip existing bots, so I'll remove as approriate once the try jobs finished
and open appropriate bugs for the non trivial cases.

[Mark Seaborn, 2013-08-21 17:49:33]

LGTM

https://codereview.chromium.org/23123011/diff/1/content/zygote/zygote_linux.cc
File content/zygote/zygote_linux.cc (left):

https://codereview.chromium.org/23123011/diff/1/content/zygote/zygote_linux.c...
content/zygote/zygote_linux.cc:290: if (!(use_helper || UsingSUIDSandbox())) {
I assume you've tested the removal of this by running Chromium with the SUID
sandbox disabled?  I don't think that will be tested by the bots now.

[jln (very slow on Chromium), 2013-08-21 19:22:32]

https://chromiumcodereview.appspot.com/23123011/diff/1/content/zygote/zygote_...
File content/zygote/zygote_linux.cc (left):

https://chromiumcodereview.appspot.com/23123011/diff/1/content/zygote/zygote_...
content/zygote/zygote_linux.cc:290: if (!(use_helper || UsingSUIDSandbox())) {
On 2013/08/21 17:49:33, Mark Seaborn wrote:
> I assume you've tested the removal of this by running Chromium with the SUID
> sandbox disabled?  I don't think that will be tested by the bots now.

Yes, that was tested. We still have a few bots without the sandbox, including
some of the ASAN bots.

[commit-bot: I haz the power, 2013-08-21 19:27:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jln@chromium.org/23123011/1

[jln (very slow on Chromium), 2013-08-21 19:56:41]

Committed patchset #1 manually as r218806 (presubmit successful).