I don't know if there are so many facts behind your assertion that Google is going in a more and more closed direction.

Is it because they took more time than previously to open Android 3.0? It has been settled, right? And we know the reasons.

Did they slow down on releasing open-source softwares? Maybe, I don't follow it closely enough to decide.

Chromium is still open.

They did shut down some APIs, but this is a normal process of refactoring, removing stones you have on your way.

I see a recent strong trend in Google evolution, but it is not toward walled garden or closed formats or else. It is toward more and more design, ajaxy things, prettiness, and I think it is a bit unnecessary, and they may have to revert some of these changes.