Add a script to generate HTML and DOM docs with cross-links to one another.

utils/dartdoc/files.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.
 
 // Functions for working with files and paths.
 
 /** The path to the file currently being written to, relative to [outdir]. */
 String _filePath;
 
 /** The file currently being written to. */
 StringBuffer _file;
 
-FileSystem files;
-
 startFile(String path) {
   _filePath = path;
   _file = new StringBuffer();
 }
 
 write(String s) {
   _file.add(s);
 }
 
 writeln(String s) {
   write(s);
   write('\n');
 }
 
 endFile() {
   String outPath = '$outdir/$_filePath';
-  files.createDirectory(dirname(outPath), recursive: true);
+  world.files.createDirectory(dirname(outPath), recursive: true);
 
   world.files.writeString(outPath, _file.toString());
   _filePath = null;
   _file = null;
 }
 
 /**
  * Converts [absolute] which is understood to be a full path from the root of
  * the generated docs to one relative to the current file.
  */
@@ skipping 12 matching lines @@
   // If the type isn't generic, genericType returns `this`, so it works for
   // non-generic types too.
   return '${sanitize(type.library.name)}/${type.genericType.name}.html';
 }
 
 /** Gets the URL for the documentation for [member]. */
 memberUrl(Member member) => '${typeUrl(member.declaringType)}#${member.name}';
 
 /** Gets the anchor id for the document for [member]. */
 memberAnchor(Member member) => '${member.name}';