sandwich: Fixes some failures in request_track.py

sandwich: Fixes some failures in request_track.py

This CL fixes the following failures in request_track.py:
 - Data protocol are known to have encodedDataLength == 0
 - Some request_id might be duplicated and this CL just ignore the
   duplicated errors.

BUG=623966
Committed: https://crrev.com/08ade9ccbfd03bcef642262243542f83bb6776e8
Cr-Commit-Position: refs/heads/master@{#403432}

[gabadie, 2016-06-30 12:24:26]

gabadie@chromium.org changed reviewers:
+ mattcary@chromium.org

[mattcary, 2016-06-30 13:48:19]

lgtm

Thanks for adding tests!

[gabadie, 2016-06-30 18:29:48]

gabadie@chromium.org changed reviewers:
+ blundell@chromium.org

[gabadie, 2016-06-30 18:29:49]

Adding blundell. PTAL.

[blundell, 2016-07-01 08:55:01]

lgtm

[gabadie, 2016-07-01 09:04:57]

On 2016/07/01 08:55:01, blundell wrote:
> lgtm

Thanks Guys! Landing.

[gabadie, 2016-07-01 09:05:01]

The CQ bit was checked by gabadie@chromium.org

[commit-bot: I haz the power, 2016-07-01 09:05:13]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-01 10:03:10]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-01 10:05:39]

Description was changed from

==========
sandwich: Fixes some failures in request_track.py

This CL fixes the following failures in request_track.py:
 - Data protocol are known to have encodedDataLength == 0
 - Some request_id might be duplicated and this CL just ignore the
   duplicated errors.

BUG=623966
==========

to

==========
sandwich: Fixes some failures in request_track.py

This CL fixes the following failures in request_track.py:
 - Data protocol are known to have encodedDataLength == 0
 - Some request_id might be duplicated and this CL just ignore the
   duplicated errors.

BUG=623966

Committed: https://crrev.com/08ade9ccbfd03bcef642262243542f83bb6776e8
Cr-Commit-Position: refs/heads/master@{#403432}
==========

[commit-bot: I haz the power, 2016-07-01 10:05:40]

Patchset 1 (id:??) landed as
https://crrev.com/08ade9ccbfd03bcef642262243542f83bb6776e8
Cr-Commit-Position: refs/heads/master@{#403432}