pkg/csslib: fixed analysis error, more cleanup

pkg/csslib/lib/src/tree_base.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of csslib.visitor;
 
 /**
  * The base type for all nodes in a CSS abstract syntax tree.
  */
 abstract class TreeNode {
@@ skipping 59 matching lines @@
     if (node != null) node.visit(printer);
     else writeln('null');
     depth -= 1;
   }
 
   void writeValue(String label, value) {
     var v = toValue(value);
     writeln('${label}: ${v}');
   }
 
-  void writeList(String label, List<TreeNode> list) {
-    write('${label}: ');
-    if (list == null) {
-      buf.write('null');
-      buf.write('\n');
-    } else {
-      for (var item in list) {
-        buf.write(item.toString());
-        buf.write(', ');
-      }
-      buf.write('\n');
-    }
-  }
-
   void writeNodeList(String label, List<TreeNode> list) {
     writeln('${label} [');
     if (list != null) {
       depth += 1;
       for (var node in list) {
         if (node != null) {
           node.visit(printer);
         } else {
           writeln('null');
         }
       }
       depth -= 1;
       writeln(']');
     }
   }
 
   String toString() => buf.toString();
 }