Remove unused RenderIO() interface.

Remove unused RenderIO() interface.

BUG=337096
TEST=bots

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=271536

[no longer working on chromium, 2014-05-19 19:32:18]

Hi Dale, this should be the last piece of chromium code about the unified IO.
Please review.

Thanks,
SX

[DaleCurtis, 2014-05-19 19:38:43]

lgtm

[no longer working on chromium, 2014-05-19 19:42:13]

The CQ bit was checked by xians@chromium.org

[commit-bot: I haz the power, 2014-05-19 19:42:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/xians@chromium.org/293673004/1

[commit-bot: I haz the power, 2014-05-19 21:41:06]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)
  linux_chromium_chromeos_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome...)

[commit-bot: I haz the power, 2014-05-19 22:20:00]

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

[commit-bot: I haz the power, 2014-05-19 22:20:01]

Try jobs failed on following builders:
  linux_chromium_chromeos_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_chrome...)

[DaleCurtis, 2014-05-20 00:47:41]

The CQ bit was checked by dalecurtis@chromium.org

[DaleCurtis, 2014-05-20 00:47:45]

Note there's still one more piece: AudioParameters::input_channels().

[commit-bot: I haz the power, 2014-05-20 00:48:18]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/xians@chromium.org/293673004/1

[commit-bot: I haz the power, 2014-05-20 02:19:52]

Change committed as 271536