Tweak style for cr.ui tabbox slightly
Tweak style for cr.ui tabbox slightly

Changed selected style to a background color change instead of a
font-weight change to avoid changing tab widths.

BUG=
TEST=

Review URL: http://codereview.chromium.org/6596088

git-svn-id: http://src.chromium.org/svn/trunk/src@76647 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 033966d6c7ff33f48a9ad8d2ce75af93762186d3
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser