Make IDN check faster by caching the exemplar sets
Make IDN check faster by caching the exemplar sets

BUG=NONE
TEST=Pass NetUti*.IDN* (net_unittest) and NetUtil*.IDN*Slow runs much faster than before (~ 20 times). 
     
Review URL: http://codereview.chromium.org/149577

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@20666 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser