This makes it possible to access cameras through xdg-desktop-portal and
pipewire.
For pipewire, a shared state is needed between the enumeration and the
creation of camera object. So a new API is needed with a shared options
object that holds the state and can be used to choose which backend to try.
Bug: webrtc:13177
Change-Id: Iaad2333b41e4e6fb112f4558ea4b623e59afcbd1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/261620
Reviewed-by: Alexander Cooper <alcooper@chromium.org>
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39251}
