Filter mandatory constraints for getDisplayMedia()

Update to the spec suggests that we now enable certain constraints in
getDisplayMedia() call. This CL will allow them from higher level and update
wpt tests. Note that actual application of constraints will follow in the next
CLs.

Bug: 326740
Change-Id: I1f0b3c9b7a2feab7b17ee79c8c2420d9ced7fda8
Reviewed-on: https://chromium-review.googlesource.com/c/1284733
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600519}
5 files changed