Consider merging https://chromium.googlesource.com/chromium/blink/+/ff783a23bb1add588971a8187048a305cf485121 This patch adds the functionality to list which webcams/micophones are available
This API changed shortly after the patch landed, so it doesn't make sense to merge it by itself. Instead, I will merge the changes for this revision with https://webkit.org/b/120883.