mozilla-b2g/gaia — pull request #24456 by jrburke (2014-09-26 04:39:17+00:00)
Title: Bug 1073356 - [Calendar] Wobbly Refresh Icon Animation

Use the span element inside the button to give it a fixed size that matches the background size, and rely on the auto centering that was already possible within the container and by margin: 0 auto.