Add thread safety annotations for some more PeerConnection members (part 4)
Add thread safety annotations for some more PeerConnection members (part 4)

Plus all the annotations that were necessary to make things compile
again.

Bug: webrtc:9987
Change-Id: Ia421e4dc0e1bbc81c3976cc7530d44de934d33bb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128882
Reviewed-by: Steve Anton <93f73658da16553b94c040887a439a155812e54e@webrtc.org>
Commit-Queue: Karl Wiberg <2c708eb0a58047bf403399f50b3da33ffd2dd444@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#27257}
TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc