Add new codec for FlexFEC.

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

Index: webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpCodecParameters.h
diff --git a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpCodecParameters.h b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpCodecParameters.h
index fef8429803c00713f6c2739d099a060ca9702746..a3156bb9cd3185c4115abd4ae0db4f0d9a618262 100644
--- a/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpCodecParameters.h
+++ b/webrtc/sdk/objc/Framework/Headers/WebRTC/RTCRtpCodecParameters.h
@@ -17,6 +17,7 @@ NS_ASSUME_NONNULL_BEGIN
 RTC_EXTERN const NSString * const kRTCRtxCodecMimeType;
 RTC_EXTERN const NSString * const kRTCRedCodecMimeType;
 RTC_EXTERN const NSString * const kRTCUlpfecCodecMimeType;
+RTC_EXTERN const NSString * const kRTCFlexfecCodecMimeType;
 RTC_EXTERN const NSString * const kRTCOpusCodecMimeType;
 RTC_EXTERN const NSString * const kRTCIsacCodecMimeType;
 RTC_EXTERN const NSString * const kRTCL16CodecMimeType;