Removed obsolete code

utils/css/treebase.dart

-// Copyright (c) 2011, 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.
-/**
- * The base type for all nodes in a dart abstract syntax tree.
- */
-class ASTNode {
-  /** The source code this [ASTNode] represents. */
-  SourceSpan span;
-
-  ASTNode(this.span) {}
-
-  /** Classic double-dispatch visitor for implementing passes. */
-  abstract visit(TreeVisitor visitor);
-
-  /** A multiline string showing the node and its children. */
-  String toDebugString() {
-    var to = new TreeOutput();
-    var tp = new TreePrinter(to);
-    this.visit(tp);
-    return to.buf.toString();
-  }
-}
-
-/** The base type for expressions. */
-// TODO(terry): Should be abstract class; but frog doesn't support abstract.
-class Expression extends ASTNode {
-  Expression(SourceSpan span): super(span);
-
-  visit(TreeVisitor visitor) {}   // TODO(terry): remove when abstract.
-}
-
-/** The base type for a reference to a [Type]. */
-// TODO(terry): Should be abstract class; but frog doesn't support abstract.
-class TypeReference extends ASTNode {
-  TypeReference(SourceSpan span): super(span);
-
-  visit(TreeVisitor visitor) {}   // TODO(terry): remove when abstract.
-}
-
-// TODO(jimhug): Clean-up and factor out of core.
-/** Simple class to provide a textual dump of trees for debugging. */
-class TreeOutput {
-  int depth;
-  StringBuffer buf;
-
-  var printer;
-
-  static void dump(ASTNode node) {
-    var o = new TreeOutput();
-    node.visit(new TreePrinter(o));
-    print(o.buf);
-  }
-
-  TreeOutput(): this.depth = 0, this.buf = new StringBuffer() {
-  }
-
-  void write(String s) {
-    for (int i=0; i < depth; i++) {
-      buf.write(' ');
-    }
-    buf.write(s);
-  }
-
-  void writeln(String s) {
-    write(s);
-    buf.write('\n');
-  }
-
-  void heading(String name, span) {
-    write(name);
-    buf.write('  (${span.locationText})');
-    buf.write('\n');
-  }
-
-  String toValue(value) {
-    if (value == null) return 'null';
-    else if (value is Identifier) return value.name;
-    else return value.toString();
-  }
-
-  void writeNode(String label, ASTNode node) {
-    write(label + ': ');
-    depth += 1;
-    if (node != null) node.visit(printer);
-    else writeln('null');
-    depth -= 1;
-  }
-
-  void writeValue(String label, value) {
-    var v = toValue(value);
-    writeln('${label}: ${v}');
-  }
-
-  void writeList(String label, List list) {
-    write(label + ': ');
-    if (list == null) {
-      buf.write('null');
-      buf.write('\n');
-    } else {
-      for (var item in list) {
-        buf.write(item.toString());
-        buf.write(', ');
-      }
-      buf.write('\n');
-    }
-  }
-
-  void writeNodeList(String label, List list) {
-    writeln('${label} [');
-    if (list != null) {
-      depth += 1;
-      for (var node in list) {
-        if (node != null) {
-          node.visit(printer);
-        } else {
-          writeln('null');
-        }
-      }
-      depth -= 1;
-      writeln(']');
-    }
-  }
-}