WIP M67 - plumb through AVCaptureSession

TODO:

-[x] plumb through AVCaptureSession
-[] get AVCaptureSession from PeerConnectionClient
-[] RTCDataChannel not unwrapped
-[] no member avFoundationSource
-[] no member "back camera"

Signal/src/ViewControllers/CallViewController.swift

@@ -73,6 +73,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
     var localVideoView: RTCCameraPreviewView!
     var hasShownLocalVideo = false
     weak var localVideoTrack: RTCVideoTrack?
+    weak var localCaptureSession: AVCaptureSession?
     weak var remoteVideoTrack: RTCVideoTrack?
 
     override public var canBecomeFirstResponder: Bool {
@@ -1001,18 +1002,19 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
 
     // MARK: - Video
 
-    internal func updateLocalVideoTrack(localVideoTrack: RTCVideoTrack?) {
+    // MJK TODO remove localVideoTrack?
+    internal func updateLocalVideoTrack(localVideoTrack: RTCVideoTrack?,
+                                        captureSession: AVCaptureSession?) {
+
         SwiftAssertIsOnMainThread(#function)
         guard self.localVideoTrack != localVideoTrack else {
             return
         }
 
         self.localVideoTrack = localVideoTrack
+        localVideoView.captureSession = captureSession
+        let isHidden = captureSession == nil
 
-        let source = localVideoTrack?.source as? RTCAVFoundationVideoSource
-
-        localVideoView.captureSession = source?.captureSession
-        let isHidden = source == nil
         Logger.info("\(TAG) \(#function) isHidden: \(isHidden)")
         localVideoView.isHidden = isHidden
 
@@ -1117,12 +1119,14 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
         // Do nothing.
     }
 
+    // TODO remove localCaptureSession:
     internal func didUpdateVideoTracks(call: SignalCall?,
                                        localVideoTrack: RTCVideoTrack?,
+                                       localCaptureSession: AVCaptureSession?,
                                        remoteVideoTrack: RTCVideoTrack?) {
         SwiftAssertIsOnMainThread(#function)
 
-        updateLocalVideoTrack(localVideoTrack: localVideoTrack)
+        updateLocalVideoTrack(localVideoTrack: localVideoTrack, captureSession: localCaptureSession)
         updateRemoteVideoTrack(remoteVideoTrack: remoteVideoTrack)
     }
 }

Signal/src/call/CallService.swift

@@ -93,8 +93,10 @@ protocol CallServiceObserver: class {
     /**
      * Fired whenever the local or remote video track become active or inactive.
      */
+    // TODO remove localCaptureSession:
     func didUpdateVideoTracks(call: SignalCall?,
                               localVideoTrack: RTCVideoTrack?,
+                              localCaptureSession: AVCaptureSession?,
                               remoteVideoTrack: RTCVideoTrack?)
 }
 
@@ -125,6 +127,14 @@ private class SignalCallData: NSObject {
         }
     }
 
+    weak var localCaptureSession: AVCaptureSession? {
+        didSet {
+            SwiftAssertIsOnMainThread(#function)
+
+            Logger.info("\(self.logTag) \(#function)")
+        }
+    }
+
     weak var remoteVideoTrack: RTCVideoTrack? {
         didSet {
             SwiftAssertIsOnMainThread(#function)
@@ -282,6 +292,15 @@ private class SignalCallData: NSObject {
             return callData?.localVideoTrack
         }
     }
+
+    weak var localCaptureSession: AVCaptureSession? {
+        get {
+            SwiftAssertIsOnMainThread(#function)
+
+            return callData?.localCaptureSession
+        }
+    }
+
     var remoteVideoTrack: RTCVideoTrack? {
         get {
             SwiftAssertIsOnMainThread(#function)
@@ -1622,11 +1641,10 @@ private class SignalCallData: NSObject {
         observers.append(Weak(value: observer))
 
         // Synchronize observer with current call state
-        let call = self.call
-        let localVideoTrack = self.localVideoTrack
         let remoteVideoTrack = self.isRemoteVideoEnabled ? self.remoteVideoTrack : nil
-        observer.didUpdateVideoTracks(call: call,
-                                      localVideoTrack: localVideoTrack,
+        observer.didUpdateVideoTracks(call: self.call,
+                                      localVideoTrack: self.localVideoTrack,
+                                      localCaptureSession: self.localCaptureSession,
                                       remoteVideoTrack: remoteVideoTrack)
     }
 
@@ -1649,13 +1667,11 @@ private class SignalCallData: NSObject {
     private func fireDidUpdateVideoTracks() {
         SwiftAssertIsOnMainThread(#function)
 
-        let call = self.call
-        let localVideoTrack = self.localVideoTrack
         let remoteVideoTrack = self.isRemoteVideoEnabled ? self.remoteVideoTrack : nil
-
         for observer in observers {
-            observer.value?.didUpdateVideoTracks(call: call,
-                                                 localVideoTrack: localVideoTrack,
+            observer.value?.didUpdateVideoTracks(call: self.call,
+                                                 localVideoTrack: self.localVideoTrack,
+                                                 localCaptureSession: self.localCaptureSession,
                                                  remoteVideoTrack: remoteVideoTrack)
         }
     }

Signal/src/call/PeerConnectionClient.swift

@@ -235,7 +235,7 @@ class PeerConnectionClient: NSObject, RTCPeerConnectionDelegate, RTCDataChannelD
     private var videoCaptureSession: AVCaptureSession?
     private var videoSender: RTCRtpSender?
     private var localVideoTrack: RTCVideoTrack?
-    private var localVideoSource: RTCAVFoundationVideoSource?
+    private var localVideoSource: RTCVideoSource?
 
     // RTCVideoTrack is fragile and prone to throwing exceptions and/or
     // causing deadlock in its destructor.  Therefore we take great care

Signal/src/call/UserInterface/CallUIAdapter.swift

@@ -273,6 +273,7 @@ extension CallUIAdaptee {
 
     internal func didUpdateVideoTracks(call: SignalCall?,
                                        localVideoTrack: RTCVideoTrack?,
+                                       localCaptureSession: AVCaptureSession?,
                                        remoteVideoTrack: RTCVideoTrack?) {
         SwiftAssertIsOnMainThread(#function)