GN: Add targets for AppRTCDemo on Mac+iOS

webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m

Index: webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m
diff --git a/webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m b/webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m
index 4d58d2ad3477b9951f0307ae34edf1a625c9370e..914403619c5abf532825fd186df35ff43750d81a 100644
--- a/webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m
+++ b/webrtc/examples/objc/AppRTCDemo/mac/APPRTCViewController.m
@@ -47,12 +47,14 @@ static NSUInteger const kLogViewHeight = 280;
   NSTextField* _roomLabel;
   NSTextField* _roomField;
   NSTextView* _logView;
-  RTCNSGLVideoView* _localVideoView;
-  RTCNSGLVideoView* _remoteVideoView;
   CGSize _localVideoSize;
   CGSize _remoteVideoSize;
 }
 
+@synthesize delegate = _delegate;
+@synthesize localVideoView = _localVideoView;
+@synthesize remoteVideoView = _remoteVideoView;
+
 + (BOOL)requiresConstraintBasedLayout {
   return YES;
 }