requestFullscreen and enterFullscreen on HTMLVideoElement

[deepak786]

Currently I'm migrating the code to use web package.
I have video element.

final videoElement = web.HTMLVideoElement();

requestFullscreen and enterFullscreen methods are not available on HTMLVideoElement

videoElement.requestFullscreen();
videoElement.enterFullscreen();

[deepak786]

Similarly exitFullscreen

[deepak786]

For now I have used the extension

extension on web.HTMLVideoElement {
  external JSPromise requestFullscreen();

  external JSPromise enterFullscreen();
}

[srujzs]

requestFullscreen and exitFullscreen should be addressed in #209, but I'm not sure enterFullscreen still exists as part of the spec: https://developer.mozilla.org/en-US/docs/Web/API/Document/exitFullscreen.