getComputedStyle now returns used values for top, left, bottom, right

getComputedStyle now returns used values for the top, left, bottom, and
right properties of positioned elements, instead of returning computed
values, if the display property is not None.

R=mstensho@opera.com
BUG=589347

Review URL: https://codereview.chromium.org/1826423003

Cr-Commit-Position: refs/heads/master@{#385493}
12 files changed