Apple certainly won't accept bitcoin, especially not in the near future. They seem quite serious about their Apple Pay system. Bitcoin is pretty much their enemy right now, i would assume.

Microsoft has taken some VERY strange steps lately. They seem to make some big changes, and i really like them. (open source .NET for example)
Perhaps this move to bitcoin is another step in their big plan to change their stategy.

I can see google taking the step, but then again, i find google quite hard to predict sometimes.