web-ui settings: Font setting fixes and improvements.
- Add back settings for serif & sans-serif fonts.
- Remove font size setting for monospace fonts.
- As a result of these changes, the default font size now matches the 'Medium' setting.

BUG=10524,74077,71482
TEST=Verify that options in font settings dialog work properly.
Review URL: http://codereview.chromium.org/6672063

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@78474 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed