Add breaks in switch statement to fix AppRTCDemo crash

webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m

Index: webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m
diff --git a/webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m b/webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m
index c9bc3f19b0a1b770c4d2aa8cb3f6444dec71be28..6dd04cc6e02e4d3df90dda19f2e5a096049e0c42 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m
+++ b/webrtc/examples/objc/AppRTCDemo/ARDSignalingMessage.m
@@ -94,11 +94,14 @@ static NSString const *kARDSignalingMessageTypeKey = @"type";
   switch (sdpType) {
     case RTCSdpTypeOffer:
       messageType = kARDSignalingMessageTypeOffer;
+      break;
     case RTCSdpTypeAnswer:
       messageType = kARDSignalingMessageTypeAnswer;
+      break;
     case RTCSdpTypePrAnswer:
       NSAssert(NO, @"Unexpected type: %@",
           [RTCSessionDescription stringForType:sdpType]);
+      break;
   }
   if (self = [super initWithType:messageType]) {
     _sessionDescription = description;