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

tests/compiler/dart2js/backend_htype_list_test.dart

Index: tests/compiler/dart2js/backend_htype_list_test.dart
diff --git a/tests/compiler/dart2js/backend_htype_list_test.dart b/tests/compiler/dart2js/backend_htype_list_test.dart
index 7b4405963cb7389255ca94f9e7aff7d99fe17cce..67acff3457a083f2d304f8f7508ef200b5e5a9e0 100644
--- a/tests/compiler/dart2js/backend_htype_list_test.dart
+++ b/tests/compiler/dart2js/backend_htype_list_test.dart
@@ -29,7 +29,7 @@ List<HType> III;
 FunctionSignature compileAndFindSignature(String code,
                                           String className,
                                           String memberName) {
-  Uri uri = new Uri.fromComponents(scheme: 'source');
+  Uri uri = new Uri(scheme: 'source');
   var compiler = compilerFor(code, uri);
   compiler.runCompiler(uri);
   var cls = findElement(compiler, className);