Handle iOS devices with no rear-facing camera

talk/app/webrtc/objc/avfoundationvideocapturer.h

Index: talk/app/webrtc/objc/avfoundationvideocapturer.h
diff --git a/talk/app/webrtc/objc/avfoundationvideocapturer.h b/talk/app/webrtc/objc/avfoundationvideocapturer.h
index adf7b2816cf8cb2241be763f6bf44a44506a763a..1c910a84b8f0c029436f8ca3356c2ad1a9510d9e 100644
--- a/talk/app/webrtc/objc/avfoundationvideocapturer.h
+++ b/talk/app/webrtc/objc/avfoundationvideocapturer.h
@@ -56,6 +56,10 @@ class AVFoundationVideoCapturer : public cricket::VideoCapturer {
   // Returns the active capture session.
   AVCaptureSession* GetCaptureSession();
 
+  // Returns whether the rear-facing camera can be used.
+  // e.g. It can't be used because it doesn't exist.
+  bool CanUseBackCamera() const;
+
   // Switches the camera being used (either front or back).
   void SetUseBackCamera(bool useBackCamera);
   bool GetUseBackCamera() const;