message: Deprecate GetRemoteAudioSSLCertificate
  This CL adds the RTC_DEPRECATED markers.
  Cr-Commit-Position: refs/heads/master@{#32424}
diff: @@ -107,13 +107,15 @@ class PeerConnection : public PeerConnectionInternal,
  // remote side. This will become populated once the DTLS connection with the
  // peer has been completed, as indicated by the ICE connection state
  // transitioning to kIceConnectionCompleted.
  - // Note that this will be removed once we implement RTCDtlsTransport which
  - // has standardized method for getting this information.
  + // Deprecated - users should insted query the DTLS transpport for this info.
  // See https://www.w3.org/TR/webrtc/#rtcdtlstransport-interface
  - std::unique_ptr<rtc::SSLCertificate> GetRemoteAudioSSLCertificate();
  +
  + RTC_DEPRECATED std::unique_ptr<rtc::SSLCertificate>
  + GetRemoteAudioSSLCertificate();
  // Version of the above method that returns the full certificate chain.
  - std::unique_ptr<rtc::SSLCertChain> GetRemoteAudioSSLCertChain();
  + RTC_DEPRECATED std::unique_ptr<rtc::SSLCertChain>
  + GetRemoteAudioSSLCertChain();
  rtc::scoped_refptr<RtpSenderInterface> CreateSender(
  const std::string& kind,
  