Adding getParameters/setParameters APIs to RtpReceiver.

webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpReceiver.h

 /*
  *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import <Foundation/Foundation.h>
 
 #import <WebRTC/RTCMacros.h>
 #import <WebRTC/RTCMediaStreamTrack.h>
 #import <WebRTC/RTCRtpParameters.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
 RTC_EXPORT
-@protocol RTCRtpSender <NSObject>
+@protocol RTCRtpReceiver <NSObject>
 
-/** A unique identifier for this sender. */
-@property(nonatomic, readonly) NSString *senderId;
+/** A unique identifier for this receiver. */
+@property(nonatomic, readonly) NSString *receiverId;
 
 /** The currently active RTCRtpParameters, as defined in
  *  https://www.w3.org/TR/webrtc/#idl-def-RTCRtpParameters.
+ *
+ *  The WebRTC specification only defines RTCRtpParameters in terms of senders,
+ *  but this API also applies them to receivers, similar to ORTC:
+ *  http://ortc.org/wp-content/uploads/2016/03/ortc.html#rtcrtpparameters*.
  */
-@property(nonatomic, copy) RTCRtpParameters *parameters;
+@property(nonatomic, readonly) RTCRtpParameters *parameters;
 
-/** The RTCMediaStreamTrack associated with the sender.
+/** The RTCMediaStreamTrack associated with the receiver.
  *  Note: reading this property returns a new instance of
  *  RTCMediaStreamTrack. Use isEqual: instead of == to compare
  *  RTCMediaStreamTrack instances.
  */
-@property(nonatomic, copy, nullable) RTCMediaStreamTrack *track;
+@property(nonatomic, readonly) RTCMediaStreamTrack *track;
 
 @end
 
 RTC_EXPORT
-@interface RTCRtpSender : NSObject <RTCRtpSender>
+@interface RTCRtpReceiver : NSObject <RTCRtpReceiver>
 
 - (instancetype)init NS_UNAVAILABLE;
 
 @end
 
 NS_ASSUME_NONNULL_END