Linux: don't crash when performing font fallback to a non-scalable font.

Previously we were filtering out non-scalable fonts /after/ the fact.
This patch changes it so that we specify to fontconfig that it
shouldn't return non-scalable fonts to us.

We also duplicate this code into WebFontInfo so that we don't get
these issues when performing glyph-fallback.

http://codereview.chromium.org/149437
BUG=16403


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20351 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed