Base: Add Process::WaitForExit and WaitForExitWithTimeout.

Base: Add Process::WaitForExit and WaitForExitWithTimeout.

The new methods are meant to replace similar functions from kill.h

BUG=417532
Committed: https://crrev.com/126fd5821f27793535bd80642c6e87c56b2634a1
Cr-Commit-Position: refs/heads/master@{#308009}

[rvargas (doing something else), 2014-12-09 03:18:28]

rvargas@chromium.org changed reviewers:
+ cpu@chromium.org

[rvargas (doing something else), 2014-12-10 21:56:47]

On 2014/12/09 03:18:28, rvargas wrote:

ping

[cpu_(ooo_6.6-7.5), 2014-12-11 21:11:51]

that test might end up being flaky but I don't have great suggestions. I guess
we can try as is.

lgtm

[rvargas (doing something else), 2014-12-11 21:50:54]

The CQ bit was checked by rvargas@chromium.org

[commit-bot: I haz the power, 2014-12-11 23:08:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/791503002/1

[commit-bot: I haz the power, 2014-12-12 00:25:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-12 00:26:16]

Patchset 1 (id:??) landed as
https://crrev.com/126fd5821f27793535bd80642c6e87c56b2634a1
Cr-Commit-Position: refs/heads/master@{#308009}