Fix socket send.

Fix socket send.

Instead of calling CopresenceSocket::Send with the size of the packet we
created, we were calling it with the size of the original data. This CL fixes
that bug and adds more logging when we're sending data.

R=xiyuan@chromium.org
BUG=None.

Committed: https://crrev.com/89763279e7c46196bad17e9c5f31abb0ccffa2b1
Cr-Commit-Position: refs/heads/master@{#302656}

[xiyuan, 2014-11-04 19:13:24]

lgtm

[rkc, 2014-11-04 19:14:22]

The CQ bit was checked by rkc@chromium.org

[commit-bot: I haz the power, 2014-11-04 19:15:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/698153005/1

[commit-bot: I haz the power, 2014-11-04 20:23:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-04 20:25:40]

Patchset 1 (id:??) landed as
https://crrev.com/89763279e7c46196bad17e9c5f31abb0ccffa2b1
Cr-Commit-Position: refs/heads/master@{#302656}