GitLab

DeleteFileSystem will be used in Inspector to allow web developers to clear their filesystem.
And DRT support of DeleteFileSystem will help unittest of Inspector.

BUG=139366


Review URL: https://chromiumcodereview.appspot.com/10824305

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151836 0039d316-1c4b-4281-b951-d872f2087c98