Cool as Freddy was, let's not forget these are ads for google - would he have wanted his image used to shill for a giant corporation?
I will agree that there is some commercial benefit to Google for this sort of thing, but even I'm not cynical enough to think that's their rationale for doing this.
Freddie Mercury was one of my biggest heroes growing up, and I thought this was really nice (and maybe will cause a whole bunch of young people to ask "Who the hell is Freddie Mercury?").
There's no question Queen was a fully-sold-out pop band at the end. With their talent they could have easily pursued a less commercial path--and in their early albums, had a fair deal of influence from heavy metal and progressive rock--but for whatever reasons, they didn't. Not a criticism, just a fact.
It is a tribute, with at least some degree of creativity and effort put into making the video. I don't see this being exploited to gain Google any more users than, let's be honest, they would have anyway. Especially since it is on Google Japan, I would anticipate people going to the main page, watching the video, and then not even performing a search. And in instances where that does occur, Google is gaining nothing financially from something which, again, is a creative tribute.
I don't really see it as shilling at all.
Yes, this "advertises" Google, but why can't it also be a celebration of Freddie Mercury's life?
I really dislike the idea that every corporate gesture should have a sinister undertone...
Plus, keep in mind that Google created the video. As a photographer and someone who enjoys art in general, I can tell you that it's not uncommon for artists to incorporate their name (or, in this case, their company's name) into a piece of work. It's a nice way to make the art something with which one can personally connect.
Now, I'm not saying that you are incorrect in what you perceive to be some of their reasoning for this. Of course Google wants to associate the work they do with their brand identity, and this video is indeed advertising. Anything a company does is advertising, to be fair.
That said, I don't personally believe that advertising and showing support for something are mutually exclusive. Just as a company is able to get their name out there while also donating to charity, Google is capable of spreading the Google name while also paying tribute to Freddie.
I do wonder how far ahead they plan these and what the process looks like.