Respect device ids in handling requests from extensions

Respect device ids in handling requests from extensions

The extension code was hardcoded to use the default audio and video devices.
This change actually respects the requested ids (if given).

BUG=388428
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284233

[vrk (LEFT CHROMIUM), 2014-07-17 20:57:34]

Shijing: Note the TODO - didn't do the cleanup in this CL because I want to keep
it as simple as possible for merge. Will send you a follow-up CL that reduces
the code redundancy.

[no longer working on chromium, 2014-07-18 12:08:00]

On 2014/07/17 20:57:34, Victoria Kirst wrote:
> Shijing: Note the TODO - didn't do the cleanup in this CL because I want to
keep
> it as simple as possible for merge. Will send you a follow-up CL that reduces
> the code redundancy.

lgtm

[vrk (LEFT CHROMIUM), 2014-07-18 16:56:22]

The CQ bit was checked by vrk@chromium.org

[commit-bot: I haz the power, 2014-07-18 16:58:06]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/vrk@chromium.org/405483003/1

[commit-bot: I haz the power, 2014-07-18 20:29:19]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_compile_...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-07-18 22:44:57]

Change committed as 284233