I went to Google maps today, and for the first time I saw the "Bus" and "Underground" symbols on it. I've not seen this in the UK before. It appears to be getting data from Transport Direct and TFL. I've not seen this announced anywhere.
At the moment, when it comes to bus stops near me, it looks likes it's missing one and it only has info for the 84 and 84x (and not the 307, 107, 326, 384, ... basically all the buses near me that aren't the 84 aren't included). High Barnet station now has a clickable Underground symbol that brings up what lines are serve that station.