Move zoom handling for x and y properties to svg.
Compensating for effectiveZoom in svg instead, so that
x and y are more like other length values in css.
This fixes a bug where incorrect values would be returned
from getComputedStyle, and with transitions on x and y in
combination with zoom.
BUG=
400725
Committed:
https://src.chromium.org/viewvc/blink?view=rev&revision=190836