Merge the dart:uri library into dart:core and update the Uri class

sdk/lib/_internal/dartdoc/bin/dartdoc.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.
 
 /**
  * To generate docs for a library, run this script with the path to an
  * entrypoint .dart file, like:
  *
  *     $ dart dartdoc.dart foo.dart
  *
  * This will create a "docs" directory with the docs for your libraries. To
  * create these beautiful docs, dartdoc parses your library and every library
  * it imports (recursively). From each library, it parses all classes and
  * members, finds the associated doc comments and builds crosslinked docs from
  * them.
  */
 library dartdoc;
 
 import 'dart:async';
 import 'dart:io';
-import 'dart:uri';
 
 // TODO(rnystrom): Use "package:" URL (#4968).
 import '../lib/dartdoc.dart';
 import '../lib/src/dartdoc/utils.dart';
 import 'package:args/args.dart';
 import 'package:pathos/path.dart' as path;
 
 /**
  * Run this from the `lib/_internal/dartdoc` directory.
  */
@@ skipping 241 matching lines @@
   // If there is not, then check if the entrypoint is somewhere in a `lib`
   // directory.
   var parts = path.split(path.dirname(script));
   var libDir = parts.lastIndexOf('lib');
   if (libDir > 0) {
     return path.join(path.joinAll(parts.take(libDir)), 'packages');
   } else {
     return null;
   }
 }