Add allowCodecSwitching flag to RTCConfiguration.mm

Bug: webrtc:10795
Change-Id: I4d645b077bc459b05ef16641defdbd240dbd1550
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/159481
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29753}
diff --git a/sdk/objc/api/peerconnection/RTCConfiguration.h b/sdk/objc/api/peerconnection/RTCConfiguration.h
index 2c32311..13a51b9 100644
--- a/sdk/objc/api/peerconnection/RTCConfiguration.h
+++ b/sdk/objc/api/peerconnection/RTCConfiguration.h
@@ -194,6 +194,12 @@
  */
 @property(nonatomic, assign) BOOL activeResetSrtpParams;
 
+/** If the remote side support mid-stream codec switches then allow encoder
+ *  switching to be performed.
+ */
+
+@property(nonatomic, assign) BOOL allowCodecSwitching;
+
 /**
  * If MediaTransportFactory is provided in PeerConnectionFactory, this flag informs PeerConnection
  * that it should use the MediaTransportInterface.