include what you use: errno.h and string.h in content/

include what you use: errno.h and string.h in content/

Adding some missing errno.h includes for errno and
string.h for strerror in content/

Committed: https://crrev.com/720163fc735ca812ef0aa2d7ca46dc0a5d407257
Cr-Commit-Position: refs/heads/master@{#359110}

[Mostyn Bramley-Moore, 2015-11-06 23:15:08]

mostynb@opera.com changed reviewers:
+ kinuko@chromium.org

[Mostyn Bramley-Moore, 2015-11-06 23:15:08]

@kinuko: here's a small include-what-you-use fix.

[kinuko, 2015-11-11 08:15:13]

lgtm.

[Mostyn Bramley-Moore, 2015-11-11 15:37:07]

The CQ bit was checked by mostynb@opera.com

[commit-bot: I haz the power, 2015-11-11 15:37:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1417483018/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1417483018/1

[commit-bot: I haz the power, 2015-11-11 17:42:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-12 19:58:25]

Patchset 1 (id:??) landed as
https://crrev.com/720163fc735ca812ef0aa2d7ca46dc0a5d407257
Cr-Commit-Position: refs/heads/master@{#359110}