Specify 'sans-serif' as a fallback font for newtab page apps.
Specify 'sans-serif' as a fallback font for newtab page apps.

Undesired font is rendered for Japanese if only Helvetica and Arial
are specified.

BUG=chromium-os:11863
TEST=manually see new tab page font (text for 'web store', specifically)

Review URL: http://codereview.chromium.org/6349104

git-svn-id: http://src.chromium.org/svn/trunk/src@74404 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: dc9f695b464f1f559f7fb180d9367dade5812f74
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