But if Google does it only for none Google adnetworks that's going to be a huge lawsuit. The article doesn't really clarify why would it work on Google own networks because they convert to HTML5 or because they will white list their own stuff.
It's because their ad network converts stuff, at least that's the only way I can read these sentences:
Google said advertisers who are worried about having their ads switched off should consider converting their Flash artwork to HTML5. According to the cyber-goliath, "most Flash ads uploaded to [Google] AdWords are automatically converted to HTML5."
So, in other words, if you're not on Google's ad network, you're locked out of Chrome – unless you also switch to HTML5 artwork.