[Master feature] Minimize video to corner on scroll #14061
Description
Often users want to continue watching a video at the same time that they view more content on a web page (see a recipe being made at the same time as jotting down ingredient list or reading steps one by one; watching footage of a news story while reading a deeper dive on the content). This feature is to implement a UI that makes this easy: minimizing videos to the corner of the screen when the user has scrolled them sufficiently out of view. Controls should be available to pause, mute, go to fullscreen, or dismiss the video. Should integrate well with similar platform-level UIs.