Use new RTCCameraVideoCapturer in AppRTCMobile.

webrtc/examples/objc/AppRTCMobile/ARDAppClient.h

Index: webrtc/examples/objc/AppRTCMobile/ARDAppClient.h
diff --git a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.h b/webrtc/examples/objc/AppRTCMobile/ARDAppClient.h
index 933dc6b1a01bb5fb63cf45945985b620d6485fbb..87c18d0797dea3d3324358512171f1846cbe1b63 100644
--- a/webrtc/examples/objc/AppRTCMobile/ARDAppClient.h
+++ b/webrtc/examples/objc/AppRTCMobile/ARDAppClient.h
@@ -10,6 +10,7 @@
 
 #import <Foundation/Foundation.h>
 
+#import "WebRTC/RTCCameraVideoCapturer.h"
 #import "WebRTC/RTCPeerConnection.h"
 #import "WebRTC/RTCVideoTrack.h"
 
@@ -37,6 +38,9 @@ typedef NS_ENUM(NSInteger, ARDAppClientState) {
     didChangeConnectionState:(RTCIceConnectionState)state;
 
 - (void)appClient:(ARDAppClient *)client
+    didCreateLocalCapturer:(RTCCameraVideoCapturer *)localCapturer;
+
+- (void)appClient:(ARDAppClient *)client
     didReceiveLocalVideoTrack:(RTCVideoTrack *)localVideoTrack;
 
 - (void)appClient:(ARDAppClient *)client
@@ -80,4 +84,7 @@ typedef NS_ENUM(NSInteger, ARDAppClientState) {
 // Disconnects from the AppRTC servers and any connected clients.
 - (void)disconnect;
 
+// Switches between the front and the back camera.
+- (void)switchCamera;
+
 @end