Add more tests covering constraints usage in getDisplayMedia()

Bug: 326740
Change-Id: I923fb55c07424573d2a2829f8c5ef22fc4e28466
Reviewed-on: https://chromium-review.googlesource.com/c/1292371
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602709}
4 files changed