Fixes documentation generation for dart:html.

pkg/dartdoc/lib/src/mirrors/dart2js_mirror.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.
 
 library mirrors_dart2js;
 
 import 'dart:io';
 import 'dart:uri';
 
 import '../../../../../lib/compiler/compiler.dart' as diagnostics;
@@ skipping 464 matching lines @@
 class Dart2JsLibraryMirror extends Dart2JsObjectMirror
     implements LibraryMirror {
   Map<String, InterfaceMirror> _types;
   Map<String, MemberMirror> _members;
 
   Dart2JsLibraryMirror(Dart2JsMirrorSystem system, LibraryElement library)
       : super(system, library);
 
   LibraryElement get _library => _element;
 
+  Uri get uri => _library.uri;
+
   LibraryMirror library() => this;
 
   /**
    * Returns the library name (for libraries with a #library tag) or the script
    * file name (for scripts without a #library tag). The latter case is used to
    * provide a 'library name' for scripts, to use for instance in dartdoc.
    */
   String get simpleName {
     if (_library.libraryTag !== null) {
       // TODO(ahe): Remove StringNode check when old syntax is removed.
@@ skipping 894 matching lines @@
     if (node !== null) {
       var span = system.compiler.spanFromNode(node, script.uri);
       return new Dart2JsLocation(script, span);
     } else {
       var span = system.compiler.spanFromElement(_variable);
       return new Dart2JsLocation(script, span);
     }
   }
 }