It's a logical place to start given the X-Client-Data backdoor to DoubleClick and Google properties, which is fundamentally anti-competitive in the ad space by

It's a logical place to start given the X-Client-Data backdoor to DoubleClick and Google properties, which is fundamentally anti-competitive in the ad space by giving DoubleClick access to data that other ad networks are unable to obtain and making it literally impossible for Chrome users to opt out of (and not disclosing the DoubleClick relationship). Then there's the constant stream of new web APIs which are used almost exclusively for tracking purposes by ad networks including Google properties. For an example of that, look at the AudioContext APIs which leak audio latency information (regularly used to fingerprint users) and are available to websites with no opt-in, no notice and are accessible even if you never use audio on the page. Practically all of the modern web APIs spearheaded by Chrome offer yet another tracking data-point that is abused primarily by ad networks including their own.