Oh yeah, something like that wouldn't be so hard I figure and would make sense, will investigate!
An in-app web browser might be slightly harder to pull off, but I'm not 100% sure until I dig deeper. My first instinct was to do it the other way, find a way to make Chrome/Firefox be able to open up MatineeVR if there is compatible formats/playback found, would that make sense to you instead of a in-app web browser or sounds not so good?