Fixed base time in TransportFeedback message writing.

Fixed base time in TransportFeedback message writing.

Value was incorrectly truncated to 16 bits when serializing the message.
Fixed, with added regression tests.

BUG=

Committed: https://crrev.com/c8a1cccd0a80b35a5b6846f6efe6082f96c29083
Cr-Commit-Position: refs/heads/master@{#9858}

[sprang_webrtc, 2015-08-18 15:34:45]

sprang@webrtc.org changed reviewers:
+ mflodman@webrtc.org

[sprang_webrtc, 2015-08-31 13:19:07]

sprang@webrtc.org changed reviewers:
+ stefan@webrtc.org
- mflodman@webrtc.org

[sprang_webrtc, 2015-08-31 13:19:08]

Reassigning to stefan@

[stefan-webrtc, 2015-09-03 11:32:26]

lgtm

[sprang_webrtc, 2015-09-03 13:59:47]

The CQ bit was checked by sprang@webrtc.org

[commit-bot: I haz the power, 2015-09-03 13:59:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1294393002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1294393002/20001

[commit-bot: I haz the power, 2015-09-03 14:10:39]

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

[commit-bot: I haz the power, 2015-09-03 14:10:40]

Try jobs failed on following builders:
  win on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/win/builds/9470)

[sprang_webrtc, 2015-09-04 11:37:19]

The CQ bit was checked by sprang@webrtc.org

[sprang_webrtc, 2015-09-04 11:37:19]

The patchset sent to the CQ was uploaded after l-g-t-m from stefan@webrtc.org
Link to the patchset: https://codereview.webrtc.org/1294393002/#ps40001 (title:
"Constant overflow")

[commit-bot: I haz the power, 2015-09-04 11:37:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1294393002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1294393002/40001

[commit-bot: I haz the power, 2015-09-04 11:38:18]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-04 11:38:25]

Patchset 3 (id:??) landed as
https://crrev.com/c8a1cccd0a80b35a5b6846f6efe6082f96c29083
Cr-Commit-Position: refs/heads/master@{#9858}