The current Cast sink discovery tries to resolve Cast device discovered by DIAL to improve overall reliability. This bug tracks the porting of such logic to the browser / CastMediaSinkService.

Sketch implementation:
(1) Add a callback mechanism to notify CastMediaSinkService of devices discovered by DialMediaSinkService.
(2) Deduplicate with the current list of sinks. If device is new, try to resolve the device by opening a Cast channel.
(3) If successful, add sink to current sink list.

Note an optimization can be made during (2) to skip non-Cast devices. This involves patching the Cast receiver library to advertise that it is a Cast device during DIAL discovery. This optimization can b edone later.