Provide fake audio parameters when devices don't exist.

Provide fake audio parameters when devices don't exist.

These methods should always return valid parameters, even if a device
doesn't exist.

Output code will automatically fall back to a fake path at a later time
if those parameters are used to open a stream.

Input code will fail because no input devices can be enumerated.

BUG=331675
TEST=no more crashes.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=243704

[Raymond Toy (Google), 2014-01-08 20:51:14]

lgtm, but I'm not an owner.

One small nit:  would it be useful to have a method to create the default fake
audio parameters?  It's used in two places, so it makes it clearer that we want
exactly the same fake audio parameters.

[DaleCurtis, 2014-01-08 21:12:31]

I'm an owner, which is sufficient w/ your approval.

The key parts are already abstracted into global constants and I'm generally not
a fan of single line functions, so I'll keep this as is.

[Raymond Toy (Google), 2014-01-08 21:15:05]

On 2014/01/08 21:12:31, DaleCurtis wrote:
> I'm an owner, which is sufficient w/ your approval.
> 
> The key parts are already abstracted into global constants and I'm generally
not
> a fan of single line functions, so I'll keep this as is.

Sounds good.

[commit-bot: I haz the power, 2014-01-08 21:16:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dalecurtis@chromium.org/127363002/1

[commit-bot: I haz the power, 2014-01-09 00:06:38]

Change committed as 243704