Wait, are you saying there's a version of Android somewhere that ships with a web browser which actually specifies its device pixel ratio as a non-integer? I am dubious, since I assume that would force rough anti-aliasing on everything and look like crap.
The device pixel ratio is simply the conversion ratio between device pixels and css pixels. It is on the device makers to determine how to interpolate image data into CSS pixels in the browser. There are many devices that have non-integer based DPRs. From what I recall, earlier devices even have DPRs of 0.75