Sometimes YouTube introduces recaptchas only on some pages. By loading the url inside the ReCaptchaException into ReCaptchaActivity's webview, the page that originally caused the problem is shown. The user can then solve the page-specific recaptcha.
* Activities will start reCaptchaActivity with startActivityForResult and
look for RECAPTCHA_REQUEST and RESULT_OK | RESULT_CANCELED in : 'onActivityResult()'
* ReCaptchas are implemented using a simple WebView with Javascript enable.
* All HTTP responses inside the WebView are catched (using onPageFinished())
** When Google reCatcha cookies are detected, register cookies to the
Downloader class and Return to MainActivity