chameleon: XMLRPC: update the USB audio flow.

To support analog audio tests, the Raspberry Pi will use an external sound card to send/receive analog signal from 3.5mm headphone/mic port.

The XMLRPC service should detect the existance of the external sound card and choose the correct USB audio node.

BUG=b:281641828
TEST=tested locally with AudioBasicHeadphone and
AudioBasicExternalMicrophone

Change-Id: I5a3dbe9ca6fe91b505455b5ea72686e9d291382b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/chameleon/+/4530159
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
Commit-Queue: YJ Lee <yunjunlee@chromium.org>
Tested-by: YJ Lee <yunjunlee@chromium.org>
Reviewed-by: Yu-Hsuan Hsu <yuhsuan@chromium.org>
1 file changed