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

tests/compiler/dart2js/mock_compiler.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 mock_compiler;
 
 import "package:expect/expect.dart";
 import 'dart:collection';
-import 'dart:uri';
 
 import '../../../sdk/lib/_internal/compiler/compiler.dart' as api;
 import '../../../sdk/lib/_internal/compiler/implementation/elements/elements.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/resolution/resolution.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/tree/tree.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/util/util.dart';
 import 'parser_helper.dart';
 
 import '../../../sdk/lib/_internal/compiler/implementation/elements/modelx.dart'
@@ skipping 220 matching lines @@
    */
   void registerSource(Uri uri, String source) {
     sourceFiles[uri.toString()] = new MockFile(source);
   }
 
   /**
    * Used internally to create a library from a source text. The created library
    * is fixed to export its top-level declarations.
    */
   LibraryElement createLibrary(String name, String source) {
-    Uri uri = new Uri.fromComponents(scheme: "dart", path: name);
+    Uri uri = new Uri(scheme: "dart", path: name);
     var script = new Script(uri, new MockFile(source));
     var library = new LibraryElementX(script);
     parseScript(source, library);
     library.setExports(library.localScope.values.toList());
     registerSource(uri, source);
     libraries.putIfAbsent(uri.toString(), () => library);
     return library;
   }
 
   void reportWarning(Node node, var message) {
@@ skipping 134 matching lines @@
 void importLibrary(LibraryElement target, LibraryElement imported,
                    Compiler compiler) {
   for (var element in imported.localMembers) {
     compiler.withCurrentElement(element, () {
       target.addToScope(element, compiler);
     });
   }
 }
 
 LibraryElement mockLibrary(Compiler compiler, String source) {
-  Uri uri = new Uri.fromComponents(scheme: "source");
+  Uri uri = new Uri(scheme: "source");
   var library = new LibraryElementX(new Script(uri, new MockFile(source)));
   importLibrary(library, compiler.coreLibrary, compiler);
   return library;
 }
 
 class CollectingTreeElements extends TreeElementMapping {
   final Map<Node, Element> map = new LinkedHashMap<Node, Element>();
 
   CollectingTreeElements(Element currentElement) : super(currentElement);
 
   operator []=(Node node, Element element) {
     map[node] = element;
   }
 
   operator [](Node node) => map[node];
 
   void remove(Node node) {
     map.remove(node);
   }
 }
 
 class MockDeferredLoadTask extends DeferredLoadTask {
   MockDeferredLoadTask(Compiler compiler) : super(compiler);
 
   void registerMainApp(LibraryElement mainApp) {
     // Do nothing.
   }
 }