update WebRTC artifact to M72

Signal/Signal-Info.plist

@@ -9,7 +9,7 @@
 		<key>OSXVersion</key>
 		<string>10.14.2</string>
 		<key>WebRTCCommit</key>
-		<string>aa8bee9bd6f69e388a9ca7506b8702ef8ab7f195 M71</string>
+		<string>55de5593cc261fa9368c5ccde98884ed1e278ba0 M72</string>
 	</dict>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>en</string>

Signal/src/call/PeerConnectionClient.swift

@@ -171,6 +171,10 @@ class PeerConnectionProxy: NSObject, RTCPeerConnectionDelegate, RTCDataChannelDe
         self.get()?.peerConnection(peerConnection, didOpen: dataChannel)
     }
 
+    public func peerConnection(_ peerConnection: RTCPeerConnection, didChange connectionState: RTCPeerConnectionState) {
+        self.get()?.peerConnection(peerConnection, didChange: connectionState)
+    }
+
     // MARK: - RTCDataChannelDelegate
 
     public func dataChannelDidChangeState(_ dataChannel: RTCDataChannel) {
@@ -1046,6 +1050,10 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
         }
     }
 
+    internal func peerConnection(_ peerConnectionParam: RTCPeerConnection, didChange connectionState: RTCPeerConnectionState) {
+        Logger.info("didChange PeerConnectionState:\(connectionState.debugDescription)")
+    }
+
     // MARK: Helpers
 
     /**
@@ -1349,3 +1357,22 @@ fileprivate extension RTCIceConnectionState {
         }
     }
 }
+
+fileprivate extension RTCPeerConnectionState {
+    var debugDescription: String {
+        switch self {
+        case .new:
+            return "new"
+        case .connecting:
+            return "connecting"
+        case .connected:
+            return "connected"
+        case .disconnected:
+            return "disconnected"
+        case .failed:
+            return "failed"
+        case .closed:
+            return "closed"
+        }
+    }
+}

ThirdParty/WebRTC

@@ -1 +1 @@
-Subproject commit aa8bee9bd6f69e388a9ca7506b8702ef8ab7f195
+Subproject commit 55de5593cc261fa9368c5ccde98884ed1e278ba0