Add "realpath" to CrOS build deps.

Add "realpath" to CrOS build deps.

"realpath" is used by several CrOS tools.

It is needed on builders that build Chromium through the CrOS toolchain.

BUG=chromium:491287
TEST=None

Committed: https://crrev.com/6a8491d157d1613c41426e91a3ac479766dd7a31
Cr-Commit-Position: refs/heads/master@{#331434}

[dnj, 2015-05-22 19:19:14]

dnj@chromium.org changed reviewers:
+ hinoka@chromium.org, sbc@chromium.org

[dnj, 2015-05-22 19:19:14]

PTAL!

[hinoka, 2015-05-22 19:21:57]

lgtm

[dnj, 2015-05-22 20:13:59]

The CQ bit was checked by dnj@chromium.org

[commit-bot: I haz the power, 2015-05-22 20:14:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1156763002/1

[commit-bot: I haz the power, 2015-05-22 20:23:38]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-05-22 20:23:39]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[dnj, 2015-05-26 17:38:47]

ping!

[Sam Clegg, 2015-05-26 17:43:57]

On 2015/05/26 17:38:47, dnj wrote:
> ping!

You need to find someone from build/OWNERS I think.

[dnj, 2015-05-26 17:53:31]

dnj@chromium.org changed reviewers:
+ dpranke@chromium.org

[dnj, 2015-05-26 17:53:32]

Oh I'm sorry, I assumed from your presence on previous reviews that you were,
but clearly wrong.

+dpranke@

[Dirk Pranke, 2015-05-26 20:52:59]

lgtm

[dnj, 2015-05-26 20:54:50]

The CQ bit was checked by dnj@chromium.org

[commit-bot: I haz the power, 2015-05-26 20:56:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1156763002/1

[commit-bot: I haz the power, 2015-05-26 21:08:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-26 21:09:14]

Patchset 1 (id:??) landed as
https://crrev.com/6a8491d157d1613c41426e91a3ac479766dd7a31
Cr-Commit-Position: refs/heads/master@{#331434}