Remove "using" from nullable string now that all users are updated.

BUG=247723
TEST=compile works
TBR=brettw@chromium.org

Review URL: https://chromiumcodereview.appspot.com/17385006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207165 0039d316-1c4b-4281-b951-d872f2087c98


CrOS-Libchrome-Original-Commit: 5a8ccdae65377d0d2917dee3d4a6f14128594be6
1 file changed
tree: 589e3f28ff57990df3b52bedb113c2eb5d9fd4bc
  1. base/
  2. build/
  3. dbus/
  4. ipc/
  5. testing/
  6. third_party/