[WebView] [Android] Geolocation does not work inside a WebView, the permission request popup never opens

Further improvement for https://github.com/facebook/react-native/commit/f94abd3c012bd89b35b6a8165ffce1037c36cef2 is suggested:

`webView.setWebChromeClient(new WebChromeClient() {
 public void onGeolocationPermissionsShowPrompt(String origin, GeolocationPermissions.Callback callback) {
    callback.invoke(origin, true, false);
 }
});`

More details: http://stackoverflow.com/a/5423026
