[throwaway2048]

That is their 2015 10-K interesting to see that:

    "New technologies could block online ads, 
    which would harm our Google business."

has been amended to

    "New and existing technologies could affect 
    our ability to customize ads and/or could 
    block ads online, which would harm our 
    business."

So clearly Google now considers existing ad-blocking technology to be a threat to their business.

https://seekingalpha.com/filing/4328532