Adding getParameters/setParameters APIs to RtpReceiver.

This is similar to how a "receive" method is used to apply
RtpParameters to an RtpReceiver in ORTC. Currently, SetParameters
doesn't allow changing the parameters, so the main use of the API is
to retrieve the set of configured codecs. But other uses will likely
be made possible in the future.

R=glaznev@webrtc.org, pthatcher@webrtc.org, tkchin@webrtc.org

Review URL: https://codereview.webrtc.org/1917193008 .

Cr-Commit-Position: refs/heads/master@{#12761}
diff --git a/webrtc/media/engine/webrtcvoiceengine.h b/webrtc/media/engine/webrtcvoiceengine.h
index 927c21e..162abd1 100644
--- a/webrtc/media/engine/webrtcvoiceengine.h
+++ b/webrtc/media/engine/webrtcvoiceengine.h
@@ -149,9 +149,13 @@
 
   bool SetSendParameters(const AudioSendParameters& params) override;
   bool SetRecvParameters(const AudioRecvParameters& params) override;
-  webrtc::RtpParameters GetRtpParameters(uint32_t ssrc) const override;
-  bool SetRtpParameters(uint32_t ssrc,
-                        const webrtc::RtpParameters& parameters) override;
+  webrtc::RtpParameters GetRtpSendParameters(uint32_t ssrc) const override;
+  bool SetRtpSendParameters(uint32_t ssrc,
+                            const webrtc::RtpParameters& parameters) override;
+  webrtc::RtpParameters GetRtpReceiveParameters(uint32_t ssrc) const override;
+  bool SetRtpReceiveParameters(
+      uint32_t ssrc,
+      const webrtc::RtpParameters& parameters) override;
 
   bool SetPlayout(bool playout) override;
   bool PausePlayout();
@@ -230,8 +234,8 @@
     return default_recv_ssrc_ == static_cast<int64_t>(ssrc);
   }
   bool SetMaxSendBitrate(int bps);
-  bool SetChannelParameters(int channel,
-                            const webrtc::RtpParameters& parameters);
+  bool SetChannelSendParameters(int channel,
+                                const webrtc::RtpParameters& parameters);
   bool SetMaxSendBitrate(int channel, int bps);
   bool HasSendCodec() const {
     return send_codec_spec_.codec_inst.pltype != -1;