GitLab

This CL updates the EME requestMediaKeySystemAccess() stack to support
AV1. For library CDMs, it needs to be signaled during CDM registration.

In the next CL, ClearKeyCdm will be updated to actually support AV1
playback.

TBR=sorin@chromium.org
Windows.

Bug: 884898
Test: Added new test cases. Also manually tested component installer on
Change-Id: I0222136c76682db51bcf021c6bd5db3c467c271e
Reviewed-on: https://chromium-review.googlesource.com/c/1241569
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: John Rummell <jrummell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600638}