Add histogram count for getDisplayMedia()

Bug: 326740
Change-Id: I08e30219e436c6be1216b6b94e9d7c5ed5b611d0
Reviewed-on: https://chromium-review.googlesource.com/1179253
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Christian Fremerey <chfremer@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584622}
4 files changed