This question seems to come up a lot (pretty much every time a new version of Chrome is released). Previous answers such as these no longer apply (or don't work for Mac), however:
Sadly, Google seems intent on shoving this broken preview screen down our throats (The thought of someone not wanting to use their nonstandard, feature-poor alternative to a systemwide service is inconceivable to them, apparently), and the "disable" flag no longer seems to exist in recent versions.
Anyone know how to disable it in modern versions of the browser, which no longer include this option under "chrome://flags?" (OS-X specifically?)