Note that there's been several recent discussions on blink-dev about this,
eg:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/RyUSi3zdumQ
.
https://code.google.com/p/chromium/issues/detail?id=177836
The consensus was to match FF behavior and update devicePixelRatio and
associated media queries to reflect browser zoom - that this was both
consistent with the standard for the 'resolution' media query, and
sufficient for application needs (with Google Docs as an example of a very
demanding applications here). There was even rough agreement that this was
better than exposing two separate concepts (pixel ratio and browser zoom
level) to the application - that doing so would just lead to bugs and
applications should be treating both in the same way.
I don't personally have more detailed context than that, but this sounds
like a much better path than introducing another new API.
Rick