Replaced CriticalSectionWrapper with rtc::CriticalSection in rtp_rtcp module

Review URL: https://codereview.webrtc.org/1877253002

Cr-Original-Commit-Position: refs/heads/master@{#12359}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 7c9426cf38caffd5d2ed7b390188c84ba8e39bf7
33 files changed