Implement WebFileSystemImpl::directoryName.  This is needed for directory upload (including webkit layout tests).
Implement WebFileSystemImpl::directoryName.  This is needed for directory upload (including webkit layout tests).

BUG=41762
TEST=webkit layout test fast/forms/input-file-directory-upload.html

Review URL: http://codereview.chromium.org/2847056

git-svn-id: http://src.chromium.org/svn/trunk/src@52829 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 34db75cdcdce7c303cfd5622770ba2b3bec4993f
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