Fixes the java.utils.Arrays.ArrayList problem.  Do not create a covariant array for a subtype that is not visible to other types in the same package.  Updated logging for exposure information.

Review by: mmendez, spoon (pair prog)

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@2873 8db76d5a-ed1c-0410-87a9-c151d255dfc7