Work around element sizing bug in Chrome

If you highlighted a div in a clippable container, then scrolled
the page such that the contained clipped and became scrollable
(making the highlight narrower due to the scrollbar), then scrolled
back down such that the container unclipped, the highlight
wouldn't become wider again, and a white gap the size of the
(now-gone) scrollbar would be left behind.

Reported as https://code.google.com/p/chromium/issues/detail?id=387290 .
Work around this by first unsetting the width/height property,
then forcing a reflow, then unsetting the overflow-x/y property.

Change-Id: I73049c045c8d7f83898e1d4309b7edb148273e81
Merge "Work around element sizing bug in Chrome"