ReadIpHelper: Zero out before calling GetAdaptersAddresses

ReadIpHelper: Zero out before calling GetAdaptersAddresses

This is a first-ditch attempt at fixing http://crbug.com/401655.

BUG=401655
Committed: https://crrev.com/469b8770baa97d9d114df4bd97995f60fb9e39fe
Cr-Commit-Position: refs/heads/master@{#293610}

[Deprecated (see juliatuttle), 2014-09-05 19:12:24]

ttuttle@chromium.org changed reviewers:
+ mmenke@chromium.org

[Deprecated (see juliatuttle), 2014-09-05 19:12:24]

PTAL, mmenke.

[mmenke, 2014-09-05 19:19:29]

LGTM

[Deprecated (see juliatuttle), 2014-09-05 19:36:05]

The CQ bit was checked by ttuttle@chromium.org

[commit-bot: I haz the power, 2014-09-05 19:37:09]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ttuttle@chromium.org/539313002/1

[commit-bot: I haz the power, 2014-09-06 01:37:53]

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

[commit-bot: I haz the power, 2014-09-06 01:37:54]

Exceeded time limit waiting for builds to trigger.

[Deprecated (see juliatuttle), 2014-09-06 04:32:10]

The CQ bit was checked by ttuttle@chromium.org

[commit-bot: I haz the power, 2014-09-06 04:34:06]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ttuttle@chromium.org/539313002/1

[commit-bot: I haz the power, 2014-09-06 10:53:41]

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

[commit-bot: I haz the power, 2014-09-06 10:53:42]

Exceeded time limit waiting for builds to trigger.

[Deprecated (see juliatuttle), 2014-09-06 13:10:41]

The CQ bit was checked by ttuttle@chromium.org

[commit-bot: I haz the power, 2014-09-06 13:11:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ttuttle@chromium.org/539313002/1

[commit-bot: I haz the power, 2014-09-06 13:13:23]

Committed patchset #1 (id:1) as bae4324156d0b4caac5fe284dfecdb8bed2d7ecb

[commit-bot: I haz the power, 2014-09-10 03:42:21]

Patchset 1 (id:??) landed as
https://crrev.com/469b8770baa97d9d114df4bd97995f60fb9e39fe
Cr-Commit-Position: refs/heads/master@{#293610}