Fix a bug in data_sender.js.

Fix a bug in data_sender.js.

This fixes a bug where data sends that had been fully written to the
data pipe were not considered when deciding whether to cancel (or wait
for an in-progress cancel) during DataSender serialization.

Committed: https://crrev.com/1fdff9eb3c08f8d654f0b485061240cf13bd2ef7
Cr-Commit-Position: refs/heads/master@{#301537}

[Sam McNally, 2014-10-27 23:25:00]

sammc@chromium.org changed reviewers:
+ raymes@chromium.org

[raymes, 2014-10-27 23:30:15]

On 2014/10/27 23:25:00, Sam McNally wrote:

lgtm

[Sam McNally, 2014-10-27 23:41:28]

sammc@chromium.org changed reviewers:
+ rockot@chromium.org

[Sam McNally, 2014-10-27 23:41:29]

+rockot

[Ken Rockot(use gerrit already), 2014-10-27 23:48:13]

lgtm

[Sam McNally, 2014-10-27 23:50:35]

The CQ bit was checked by sammc@chromium.org

[commit-bot: I haz the power, 2014-10-27 23:52:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/678223002/1

[commit-bot: I haz the power, 2014-10-28 01:15:42]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-28 01:16:44]

Patchset 1 (id:??) landed as
https://crrev.com/1fdff9eb3c08f8d654f0b485061240cf13bd2ef7
Cr-Commit-Position: refs/heads/master@{#301537}