Move common VideoPacket initialization into VideoEncoderHelper.

Move common VideoPacket initialization into VideoEncoderHelper.

This avoids duplication of common VideoPacket initialization across
multiple encoders, making addition of new fields (e.g. the recently
added shape field) more robust.

Committed: https://crrev.com/59ed1bb4dcd82cf212e7a9b3c27e3d533e25ad2e
Cr-Commit-Position: refs/heads/master@{#293064}

[Wez, 2014-09-03 00:29:00]

wez@chromium.org changed reviewers:
+ sergeyu@chromium.org

[Wez, 2014-09-03 00:29:00]

PTAL

[Sergey Ulanov, 2014-09-03 01:11:26]

lgtm

https://codereview.chromium.org/530243002/diff/20001/remoting/codec/video_enc...
File remoting/codec/video_encoder_vpx.cc (right):

https://codereview.chromium.org/530243002/diff/20001/remoting/codec/video_enc...
remoting/codec/video_encoder_vpx.cc:289: // TODO(hclam): Make sure we get
exactly one frame from the packet.
this TODO can be removed

[Wez, 2014-09-03 01:12:08]

The CQ bit was checked by wez@chromium.org

[commit-bot: I haz the power, 2014-09-03 01:16:34]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/wez@chromium.org/530243002/20001

[commit-bot: I haz the power, 2014-09-03 04:37:46]

Committed patchset #2 (id:20001) as 08a848ed5b18a4fdcc5a2645f78048dc9f9972c9

[commit-bot: I haz the power, 2014-09-10 03:23:20]

Patchset 2 (id:??) landed as
https://crrev.com/59ed1bb4dcd82cf212e7a9b3c27e3d533e25ad2e
Cr-Commit-Position: refs/heads/master@{#293064}