dom_checker_uitest: fix three related bugs
dom_checker_uitest: fix three related bugs

1) was using the wrong path for its http expectations file, so
   it was never successfully loading the file
2) was not properly aborting when it could load a file, so it'd
   run the full http test despite not having an expectations file
3) even with that, the http test always fails.  At least it fails
   quickly now.

BUG=21321
TEST=DomCheckerTest should get faster by failing fast

Review URL: http://codereview.chromium.org/3549002

git-svn-id: http://src.chromium.org/svn/trunk/src@60905 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 1e5a8cdec4d87a157f888d65cede54c17a64c4cf
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