Change parameter type on AudioDeviceThread::Callback::Process()

Change parameter type on AudioDeviceThread::Callback::Process()

Parameter type is now uint32 to avoid saturation issues that may
happen when converting to int.

BUG=none
TEST=media_unittests pass

Committed: https://crrev.com/42f4aae371cbed6c8e3c8901c26ebf54e8fa9835
Cr-Commit-Position: refs/heads/master@{#301757}

[jrummell, 2014-10-28 23:48:11]

jrummell@chromium.org changed reviewers:
+ dalecurtis@chromium.org, scherkus@chromium.org

[jrummell, 2014-10-28 23:48:12]

PTAL. This is removing a TODO(acolwell).

[DaleCurtis, 2014-10-28 23:53:02]

lgtm

[scherkus (not reviewing), 2014-10-28 23:55:18]

lgtm

thanks for cleaning this up!

[jrummell, 2014-10-29 00:22:13]

The CQ bit was checked by jrummell@chromium.org

[commit-bot: I haz the power, 2014-10-29 00:23:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/687563004/1

[commit-bot: I haz the power, 2014-10-29 01:13:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-29 01:13:47]

Patchset 1 (id:??) landed as
https://crrev.com/42f4aae371cbed6c8e3c8901c26ebf54e8fa9835
Cr-Commit-Position: refs/heads/master@{#301757}