Add an error message for MacOSX 10.5.2 users
Add an error message for MacOSX 10.5.2 users

TBR=bradnelson

Review URL: http://codereview.chromium.org/3201005

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@56880 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools