Adding "adapter" ORTC objects on top of ChannelManager/BaseChannel/etc.

webrtc/api/rtpparameters.h

Index: webrtc/api/rtpparameters.h
diff --git a/webrtc/api/rtpparameters.h b/webrtc/api/rtpparameters.h
index f506c4031c3eacf6e923f3cea67d6f2f9586c4ee..d35615b4b504da00c483660a60d175cb6a9bb354 100644
--- a/webrtc/api/rtpparameters.h
+++ b/webrtc/api/rtpparameters.h
@@ -84,6 +84,12 @@ struct RtcpFeedback {
   //    rather than an unset "parameter" value.
   rtc::Optional<RtcpFeedbackMessageType> message_type;
 
+  // Constructors for convenience.
+  RtcpFeedback() {}
+  explicit RtcpFeedback(RtcpFeedbackType type) : type(type) {}
+  RtcpFeedback(RtcpFeedbackType type, RtcpFeedbackMessageType message_type)
+      : type(type), message_type(message_type) {}
+
   bool operator==(const RtcpFeedback& o) const {
     return type == o.type && message_type == o.message_type;
   }
@@ -184,6 +190,12 @@ struct RtpHeaderExtensionCapability {
   // TODO(deadbeef): Not implemented.
   bool preferred_encrypt = false;
 
+  // Constructors for convenience.
+  RtpHeaderExtensionCapability() {}
+  explicit RtpHeaderExtensionCapability(const std::string& uri) : uri(uri) {}
+  RtpHeaderExtensionCapability(const std::string& uri, int preferred_id)
+      : uri(uri), preferred_id(preferred_id) {}
+
   bool operator==(const RtpHeaderExtensionCapability& o) const {
     return uri == o.uri && preferred_id == o.preferred_id &&
            preferred_encrypt == o.preferred_encrypt;
@@ -216,6 +228,7 @@ struct RtpHeaderExtensionParameters {
 
 struct RtpFecParameters {
   // If unset, a value is chosen by the implementation.
+  // Works just like RtpEncodingParameters.ssrc.
   rtc::Optional<uint32_t> ssrc;
 
   FecMechanism mechanism = FecMechanism::RED;
@@ -228,6 +241,7 @@ struct RtpFecParameters {
 
 struct RtpRtxParameters {
   // If unset, a value is chosen by the implementation.
+  // Works just like RtpEncodingParameters.ssrc.
   rtc::Optional<uint32_t> ssrc;
 
   bool operator==(const RtpRtxParameters& o) const { return ssrc == o.ssrc; }
@@ -236,6 +250,9 @@ struct RtpRtxParameters {
 
 struct RtpEncodingParameters {
   // If unset, a value is chosen by the implementation.
+  // Note that the chosen value is NOT returned by GetParameters, because it
+  // may change due to an SSRC conflict, in which case the conflict is handled
+  // internally without any event.
   rtc::Optional<uint32_t> ssrc;
 
   // Can be used to reference a codec in the |codecs| member of the
@@ -249,12 +266,13 @@ struct RtpEncodingParameters {
   rtc::Optional<RtpFecParameters> fec;
 
   // Specifies the RTX parameters, if set.
-  // TODO(deadbeef): Not implemented.
+  // TODO(deadbeef): Not implemented with PeerConnection senders/receivers.
   rtc::Optional<RtpRtxParameters> rtx;
 
   // Only used for audio. If set, determines whether or not discontinuous
   // transmission will be used, if an available codec supports it. If not
   // set, the implementation default setting will be used.
+  // TODO(deadbeef): Not implemented.
   rtc::Optional<DtxStatus> dtx;
 
   // The relative priority of this encoding.
@@ -397,7 +415,7 @@ struct RtpParameters {
 
   std::vector<RtpCodecParameters> codecs;
 
-  // TODO(deadbeef): Not implemented.
+  // TODO(deadbeef): Not implemented with PeerConnection senders/receivers.
   std::vector<RtpHeaderExtensionParameters> header_extensions;
 
   std::vector<RtpEncodingParameters> encodings;