Make the default value of rtcp-mux policy to required.

webrtc/api/android/java/src/org/webrtc/PeerConnection.java

Index: webrtc/api/android/java/src/org/webrtc/PeerConnection.java
diff --git a/webrtc/api/android/java/src/org/webrtc/PeerConnection.java b/webrtc/api/android/java/src/org/webrtc/PeerConnection.java
index 359b52ead7c93d46dec05b38c9d5efbb01909bd9..ab085985195acf34f0c96ab9c4e769d2dfecee1b 100644
--- a/webrtc/api/android/java/src/org/webrtc/PeerConnection.java
+++ b/webrtc/api/android/java/src/org/webrtc/PeerConnection.java
@@ -146,7 +146,7 @@ public class PeerConnection {
     public RTCConfiguration(List<IceServer> iceServers) {
       iceTransportsType = IceTransportsType.ALL;
       bundlePolicy = BundlePolicy.BALANCED;
-      rtcpMuxPolicy = RtcpMuxPolicy.NEGOTIATE;
+      rtcpMuxPolicy = RtcpMuxPolicy.REQUIRE;
       tcpCandidatePolicy = TcpCandidatePolicy.ENABLED;
       candidateNetworkPolicy = candidateNetworkPolicy.ALL;
       this.iceServers = iceServers;