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

tests/lib/mirrors/library_uri_io_test.dart

 // Copyright (c) 2013, 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.
 
 // Test library uri for a library read as a file.
 
 library MirrorsTest;
 
 import 'dart:mirrors';
 import 'dart:io';
-import 'dart:uri';
 import '../../../pkg/unittest/lib/unittest.dart';
 
 class Class {
 }
 
 testLibraryUri(var value, Uri expectedUri) {
   var valueMirror = reflect(value);
   ClassMirror valueClass = valueMirror.type;
   LibraryMirror valueLibrary = valueClass.owner;
   expect(valueLibrary.uri, equals(expectedUri));
 }
 
 main() {
   var mirrors = currentMirrorSystem();
   test("Test current library uri", () {
     String appendSlash(String path) => path.endsWith('/') ? path : '$path/';
-    Uri cwd = new Uri.fromComponents(
+    Uri cwd = new Uri(
         scheme: 'file',
         path: appendSlash(new Path(new File('.').fullPathSync()).toString()));
     Uri uri = cwd.resolve(new Path(new Options().script).toString());
     testLibraryUri(new Class(), uri);
   });
 }