Missing controlsList property in HTMLMediaElement

TypeScript Version: 3.4.0-dev.201xxxxx

Search Terms:

controlsList HTMLMediaElement

Code

const video = $htmlVideoElement as HTMLVideoElement
video.controlsList.value = "nodownload";

Expected behavior:

Works so we can do things as shown https://googlechrome.github.io/samples/media/controlslist.html and as documented by https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/controlsList

Actual behavior:

controlsList is not valid for HTMLVideoElement

Playground Link:
https://www.typescriptlang.org/play/#src=interface%20HTMLMediaElement%20%7B%0D%0A%20%20%20%20readonly%20controlsList%3A%20DOMTokenList%20%0D%0A%7D%0D%0A%0D%0Aclass%20Greeter%20%7B%0D%0A%20%20%20%20greeting%3A%20string%3B%0D%0A%20%20%20%20constructor(message%3A%20string)%20%7B%0D%0A%20%20%20%20%20%20%20%20this.greeting%20%3D%20message%3B%0D%0A%20%20%20%20%7D%0D%0A%20%20%20%20greet()%20%7B%0D%0A%20%20%20%20%20%20%20%20return%20%22Hello%2C%20%22%20%2B%20this.greeting%3B%0D%0A%20%20%20%20%7D%0D%0A%7D%0D%0A%0D%0Alet%20greeter%20%3D%20new%20Greeter(%22world%22)%3B%0D%0A%0D%0Alet%20video%20%3D%20document.createElement('video')%20as%20HTMLVideoElement%3B%0D%0A%0D%0Avideo.controlsList.value%20%3D%20%22nodownload%22%0D%0A%0D%0Adocument.body.appendChild(video)%3B

Related Issues:
https://github.com/DefinitelyTyped/DefinitelyTyped/issues/19500

Workaround is to add and let the declarations get merged.

declare global {
  interface HTMLMediaElement {
    readonly controlsList: DOMTokenList 
  }
}

Or add an ambient type file

interface HTMLMediaElement {
    readonly controlsList: DOMTokenList;
}

interface DOMTokenList {
    /**
     * Returns the associated set as string.
     * Can be set, to change the associated attribute.
     */
    value: string;
}

Start by locating the HTMLMediaElement and DOMTokenList declarations used by the HTMLVideoElement example. Compare the documented controlsList API and its value property with the current declarations, then verify that the provided Playground code type-checks without the ambient workaround.