In Webkit r182839, but possibly in the previous build too, the native Share/Like button of Facebook does not display. It worked perfect in previous builds, in the latest Safari, Chrome, Chromium and Firefox. The similar Tweeter and G+ buttons continue displaying as usual, only Facebook is affected. You can see the problem at "www.48-flowers.com" There on the bottom of the main page the 3 buttons are aligned in a single row. Than in any of the variety ordering pages, the 3 buttons are put together in one square block on the lower part of the page to the right.
Just found out that r182848 resolved that issue. So that bug can be marked as resolved.