Adding codecs to the RtpParameters returned by an RtpSender.

webrtc/api/objc/RTCRtpParameters.mm

Index: webrtc/api/objc/RTCRtpParameters.mm
diff --git a/webrtc/api/objc/RTCRtpParameters.mm b/webrtc/api/objc/RTCRtpParameters.mm
index e8c4a44ce5fac84c5d8b0778886d1e77ab0fe7ad..5e791066df1426392099b3dd0a5f093f29b19d72 100644
--- a/webrtc/api/objc/RTCRtpParameters.mm
+++ b/webrtc/api/objc/RTCRtpParameters.mm
@@ -9,11 +9,14 @@
  */
 
 #import "RTCRtpParameters+Private.h"
+
+#import "RTCRtpCodecParameters+Private.h"
 #import "RTCRtpEncodingParameters+Private.h"
 
 @implementation RTCRtpParameters
 
 @synthesize encodings = _encodings;
+@synthesize codecs = _codecs;
 
 - (instancetype)init {
   return [super init];
@@ -28,6 +31,13 @@
                                initWithNativeParameters:encoding]];
     }
     _encodings = encodings;
+
+    NSMutableArray *codecs = [[NSMutableArray alloc] init];
+    for (const auto &codec : nativeParameters.codecs) {
+      [codecs addObject:[[RTCRtpCodecParameters alloc]
+                            initWithNativeParameters:codec]];
+    }
+    _codecs = codecs;
   }
   return self;
 }
@@ -37,6 +47,9 @@
   for (RTCRtpEncodingParameters *encoding in _encodings) {
     parameters.encodings.push_back(encoding.nativeParameters);
   }
+  for (RTCRtpCodecParameters *codec in _codecs) {
+    parameters.codecs.push_back(codec.nativeParameters);
+  }
   return parameters;
 }