Revert "Avoid critsect for protection- and qm setting callbacks in VideoSender."

This reverts commit 903c0f2e7649a2b98659286dc228447facd49bb7,
aka #8899.

TBR=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/46759004

Cr-Original-Commit-Position: refs/heads/master@{#8901}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 0828a0c09440cb7edbfacc94d362bf08414c7655
18 files changed