I think it would be a function of importing beatmaps in osu directly. Not only by www browser. It implicates a need of searching/browsing beatmaps engine in osu.
So, my idea is simple all i need to play osu is osu application.
In example, while joing the multiplayer game for which i do not have a beatmap, i simply click to download and after that i enjoy playing this song.
Simple.