Fix plugin lookup order on the Mac
Fix plugin lookup order on the Mac

BUG=24902
TEST=Go to about:plugins, and verify that plugins in ~/Library/Internet Plug-Ins come before those in /Library/Internet Plug-Ins

Review URL: http://codereview.chromium.org/276045

git-svn-id: http://src.chromium.org/svn/trunk/src@29142 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 602feaade63c993f13c9de93bf1fcb05af2e105d
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser