code: private void maybeAddGoogScopeUsage(NodeTraversal t, Node n, Node parent) {
      checkState(NodeUtil.isNameDeclaration(n));
      if (n.hasOneChild() && parent == googScopeBlock) {
        Node rhs = n.getFirstFirstChild();
        if (rhs != null && rhs.isQualifiedName()) {
          Node root = NodeUtil.getRootOfQualifiedName(rhs);
          if (root.isName()) {
            Var var = t.getScope().getVar(root.getString());
            if (var == null || (var.isGlobal() && !var.isExtern())) {
              usages.put(rhs.getQualifiedName(), rhs);
            }
          }
        }
      }
    }
docs: "var Dog = some.cute.Dog;" counts as a usage of some.cute.Dog, if it's immediately inside a
  goog.scope function.