Add FilePathTest.StripTrailingSeparators to base_unittests to test FilePath::StripTrailingSeparators.
Add FilePathTest.StripTrailingSeparators to base_unittests to test
FilePath::StripTrailingSeparators.

BUG=24692
TEST=this
Review URL: http://codereview.chromium.org/272039

git-svn-id: http://src.chromium.org/svn/trunk/src@28832 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 388058d865454e5e1bc3dd785ad8aaf9ef1df7e6
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