Corresponding change in Pepper since EnumerateDevices contract is changed.

Corresponding change in Pepper since EnumerateDevices contract is changed.
This patch keeps current Pepper API, while using the new API of EnumerateDevices from MediaStreamDispatcher.
Pepper calls StopEnumerateDevices when it receives the first enumerated result.

A new Pepper API will be created in a separate patch to make EnumerateDevices persistent.

BUG=137799

[viettrungluu, 2012-08-02 02:36:14]

http://codereview.chromium.org/10837064/diff/1/ppapi/shared_impl/ppb_audio_in...
File ppapi/shared_impl/ppb_audio_input_shared.cc (right):

http://codereview.chromium.org/10837064/diff/1/ppapi/shared_impl/ppb_audio_in...
ppapi/shared_impl/ppb_audio_input_shared.cc:148:
enumerate_devices_callback_->Run(result);
You can't use a completion callback any more. Completion callbacks are, by
definition, always run *exactly* once.

You have to define a version of the Pepper APIs, and support the old version,
providing exact (including semantic) backwards compatibility.

(So, for the implementation of the old version, in OnEnumerateDevicesComplete(),
you would still ClearAndRun(), but you would also need to stop enumeration ...
being careful to avoid/handle races.)

[wjia(left Chromium), 2012-08-05 18:26:51]

PTAL. This patch keeps current Pepper API so that I can land
http://codereview.chromium.org/10830063/.

Will do the new API in a separate patch.

[brettw, 2012-08-07 19:09:34]

LGTM, sorry for the delay