GitLab

Implement media load blocking in WebEngine, using logic in
components/media_control.

WebEngineIntegrationTest

Test: Add BlockMediaPlaybackUnblocked and BlockMediaPlaybackBlocked to
Bug: 1057860
Change-Id: I055d170fc942b2f88598e95605a9886fea413026
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2131210Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Commit-Queue: Sharon Yang <yangsharon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760104}