A patent troll is one who abuses such patents - not one who only files for them.
If Google is to be believed, they file and desire to buy these sort of patents to prevent patent trolls from trolling with said patents.
Google has promised (and so far has kept this promise) to only use patents defensively. A patent troll uses patents offensively by filing for absurd patents and then enforcing their right to the patented thing.
Given their history, I have less concern for Google being awarded these patents then a possible patent troll filing for the same patents but choosing to use them offensively.
