Fix checking default protocol client on Linux
Fix checking default protocol client on Linux

When getting the default protocol client using the system xdg-settings tool
fails, Chrome tries to use its own. The constant script name it looked for
was mistyped (as xdg_settings) which meant this would always fail.

This code path is not currently used by Chrome but will be soon.

TEST=Check setting Chrome as default browser on Linux works; check registering
     Chrome to handle protocols works.


Review URL: http://codereview.chromium.org/7972011

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@102079 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,ropik/chromium