Ensure audio service observation of call is always correctly wired up.

// FREEBIE

Signal/src/call/CallService.swift

@@ -82,6 +82,11 @@ fileprivate let timeoutSeconds = 60
 
 // All Observer methods will be invoked from the main thread.
 protocol CallServiceObserver: class {
+    /**
+     * Fired whenever the call changes.
+     */
+    func didUpdateCall(call: SignalCall?)
+
     /**
      * Fired whenever the local or remote video track become active or inactive.
      */
@@ -132,6 +137,10 @@ protocol CallServiceObserver: class {
             call?.addObserverAndSyncState(observer: self)
 
             updateIsVideoEnabled()
+
+            for observer in observers {
+                observer.value?.didUpdateCall(call:call)
+            }
         }
     }
 

Signal/src/call/UserInterface/CallUIAdapter.swift

@@ -5,6 +5,7 @@
 import Foundation
 import PromiseKit
 import CallKit
+import WebRTC
 
 protocol CallUIAdaptee {
     var notificationsAdapter: CallNotificationsAdapter { get }
@@ -60,7 +61,7 @@ extension CallUIAdaptee {
  * Notify the user of call related activities.
  * Driven by either a CallKit or System notifications adaptee
  */
-@objc class CallUIAdapter: NSObject {
+@objc class CallUIAdapter: NSObject, CallServiceObserver {
 
     let TAG = "[CallUIAdapter]"
     private let adaptee: CallUIAdaptee
@@ -86,13 +87,15 @@ extension CallUIAdaptee {
         }
 
         audioService = CallAudioService(handleRinging: adaptee.hasManualRinger)
+
+        super.init()
+
+        callService.addObserverAndSyncState(observer: self)
     }
 
     internal func reportIncomingCall(_ call: SignalCall, thread: TSContactThread) {
         AssertIsOnMainThread()
 
-        call.addObserverAndSyncState(observer: audioService)
-
         let callerName = self.contactsManager.displayName(forPhoneIdentifier: call.remotePhoneNumber)
         adaptee.reportIncomingCall(call, callerName: callerName)
     }
@@ -108,8 +111,6 @@ extension CallUIAdaptee {
         AssertIsOnMainThread()
 
         let call = adaptee.startOutgoingCall(handle: handle)
-        call.addObserverAndSyncState(observer: audioService)
-
         return call
     }
 
@@ -207,4 +208,20 @@ extension CallUIAdaptee {
 
         return adaptee.hasManualRinger
     }
+
+    // MARK: - CallServiceObserver
+
+    internal func didUpdateCall(call: SignalCall?) {
+        AssertIsOnMainThread()
+
+        call?.addObserverAndSyncState(observer: audioService)
+    }
+
+    internal func didUpdateVideoTracks(localVideoTrack: RTCVideoTrack?,
+                                       remoteVideoTrack: RTCVideoTrack?) {
+        AssertIsOnMainThread()
+
+        // Do nothing.
+    }
+
 }

Signal/src/view controllers/CallViewController.swift

@@ -774,6 +774,10 @@ class CallViewController: UIViewController, CallObserver, CallServiceObserver, R
 
     // MARK: - CallServiceObserver
 
+    internal func didUpdateCall(call: SignalCall?) {
+        // Do nothing.
+    }
+
     internal func didUpdateVideoTracks(localVideoTrack: RTCVideoTrack?,
                                        remoteVideoTrack: RTCVideoTrack?) {
         AssertIsOnMainThread()