Revert "Subpixel precision for clientWidth, offsetWidth, scrollTop et al"

Revert back to full pixel precision for the clientHeight, clientWidth,
clientLeft, clientTop, scrollTop, scrollLeft, scrollWidth, scrollHeight,
offsetWidth, offsetHeight, offsetTop, and offsetLeft properties.

Turns out the world isn't quite ready for these to return values with subpixel
precision.

This reverts r173426 [1].

BUG=378052, 382889, 380146, 386500
R=pdr@chromium.org

1: https://src.chromium.org/viewvc/blink?revision=173426&view=revision

Review URL: https://codereview.chromium.org/340903002

git-svn-id: svn://svn.chromium.org/blink/trunk@176545 bbb929c8-8fbe-4397-9dbb-9b2b20218538