Chrome beta (version 34) now includes native 'srcset' support: http://www.chromestatus.com/features/4644337115725824
This means that on high-density screens like a Retina MacBook Pro, the 1.5x or 2.0x-size image will be loaded automatically by the browser, and our JavaScript hack disables itself. I've confirmed that this works as expected with Chrome 34 beta and 35 'canary' builds.
This means faster page loads on hi-dpi devices and less unnecessary default loading of 1.0x-size images when they're not going to be used.
Presumably this is also coming to Chrome for Android, where it's more important due to the large number of Android devices running at 1.5 or 2.0 (or even 3.0) display density (hdpi/xhdpi/xxhdpi): http://developer.android.com/about/dashboards/index.html#Screens
-- brion