Fixed issue that was causing ERROR log messages due to duplicate cssmap file names.
Since there may be multiple css resources with the same base subtype (e.g. CssResource), the subtype class is not
guaranteed to be unique. Instead, the qualified resource getter method name is used which is unique.

Review by: unnurg@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10678 8db76d5a-ed1c-0410-87a9-c151d255dfc7