Roll Observatory packages and add a roll script

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 {
-  /** The source code this [TreeNode] represents. */
-  final SourceSpan span;
-
-  TreeNode(this.span);
-
-  TreeNode clone();
-
-  /** Classic double-dispatch visitor for implementing passes. */
-  void visit(VisitorBase visitor);
-
-  /** A multiline string showing the node and its children. */
-  String toDebugString() {
-    var to = new TreeOutput();
-    var tp = new _TreePrinter(to, true);
-    this.visit(tp);
-    return to.buf.toString();
-  }
-}
-
-/** The base type for expressions. */
-abstract class Expression extends TreeNode {
-  Expression(SourceSpan span) : super(span);
-}
-
-/** Simple class to provide a textual dump of trees for debugging. */
-class TreeOutput {
-  int depth = 0;
-  final StringBuffer buf = new StringBuffer();
-  VisitorBase printer;
-
-  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);
-    if (span != null) {
-      buf.write('  (${span.message('')})');
-    }
-    buf.write('\n');
-  }
-
-  String toValue(value) {
-    if (value == null) return 'null';
-    else if (value is Identifier) return value.name;
-    else return value.toString();
-  }
-
-  void writeNode(String label, TreeNode node) {
-    write('${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}: ${v}');
-  }
-
-  void writeNodeList(String label, List<TreeNode> list) {
-    writeln('${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();
-}