I refer to http://www.google.com/support/forum/p/Chrome/thread?tid=389f306a52817110&hl=en.
Modify (or Add) webkit data structure in following file:
- Windows XP: ..\Documents and Settings\User_Name\Local Settings\Application Data\Google\Chrome\User Data\Default\Preference
- Mac OS X: $HOME/Users/breadncup/Library/Application Support/Google/Chrome/Default/Preference
"webkit": { "webprefs": { "default_fixed_font_size": 11, "default_font_size": 12, "fixed_font_family": "Bitstream Vera Sans Mono", "minimum_font_size": 12, "minimum_logical_font_siz": 12, "sansserif_font_family": "Times New Roman", "serif_font_family": "Arial", "standard_font_is_serif": false, "text_areas_are_resizable": true } }