Fix incorrect QuotesData comparison

The original comparison was just compare the pointers, causing
false-positive of style change.

BUG=368858
R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/264713003

git-svn-id: svn://svn.chromium.org/blink/trunk@173126 bbb929c8-8fbe-4397-9dbb-9b2b20218538