В пользовательских вкладках Chrome кнопка закрытия по умолчанию не работает.

Ответ Swift 4 с кодом видеокамеры и делегатом imagePicker:

import MobileCoreServices

Открыть видеокамеру

   @IBAction func openVideoCamera(_ sender: Any) {
     if UIImagePickerController.isSourceTypeAvailable(.camera) {
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.sourceType = .camera
        imagePicker.mediaTypes = [kUTTypeMovie as String]
        imagePicker.videoMaximumDuration = 10 // or whatever you want
        imagePicker.videoQuality = .typeMedium
        imagePicker.allowsEditing = false
        present(imagePicker, animated: true, completion: nil)
    }

Делегат ImagePicker:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    let mediaType = info[UIImagePickerControllerMediaType] as AnyObject

    if mediaType as! String == kUTTypeMovie as String {
            let videoURL = info[UIImagePickerControllerMediaURL] as? URL
            print("VIDEO URL: \(videoURL!)")
    }
    dismiss(animated: true, completion: nil)
}