devices(withMediaType:) is deprecated in IOS 10

[aleene]

We are supposed to use AVCaptureDeviceDiscoverySession.

not sure how I should change this.

[yeahdongcn]

Currently I'm using

AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)

[aleene]

I changed captureDevice() to this, in order to remove the compiler warning:

` func captureDevice() -> AVCaptureDevice? { let allTypes = [AVCaptureDeviceType.builtInDuoCamera, AVCaptureDeviceType.builtInWideAngleCamera, AVCaptureDeviceType.builtInTelephotoCamera ]

    if let currentSession = AVCaptureDeviceDiscoverySession.init(deviceTypes: allTypes, mediaType: AVMediaTypeVideo, position: (self.device?.position)!) {
        if let validDevices = currentSession.devices {
            for device in validDevices {

                if self.device?.position == AVCaptureDevicePosition.back {
                    if device.position == AVCaptureDevicePosition.front {
                        return device
                    }
                } else if self.device?.position == AVCaptureDevicePosition.front {
                    if device.position == AVCaptureDevicePosition.back {
                        return device
                    }
                }
            }
        }
    }
    return nil
}

`