dart2js: add --preserve-uris flag.

tests/lib/mirrors/mirrors_test.dart

 // Copyright (c) 2011, 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 MirrorsTest;
 
 import 'dart:mirrors';
 
 import '../../light_unittest.dart';
 
@@ skipping 188 matching lines @@
 
   expect(variableMirror.simpleName, equals(#field));
   expect(variableMirror.qualifiedName,
          equals(const Symbol('MirrorsTest.Class.field')));
 }
 
 testLibraryUri(var value, bool check(Uri)) {
   var valueMirror = reflect(value);
   ClassMirror valueClass = valueMirror.type;
   LibraryMirror valueLibrary = valueClass.owner;
-  expect(check(valueLibrary.uri), isTrue);
+  Uri uri = valueLibrary.uri;
+  if (uri.scheme != "https" ||
+      uri.host != "dartlang.org" ||
+      uri.path != "/dart2js-stripped-uri") {
+    expect(check(uri), isTrue);
+  }
 }
 
 main() {
   var mirrors = currentMirrorSystem();
   test("Test reflective method invocation", () { testInvoke(mirrors); });
   test('Test intercepted objects', () { testIntercepted(mirrors); });
   test("Test field access", () { testFieldAccess(mirrors); });
   test("Test closure mirrors", () { testClosureMirrors(mirrors); });
   test("Test invoke constructor", () { testInvokeConstructor(mirrors); });
   test("Test current library uri", () {
     testLibraryUri(new Class(),
       // TODO(floitsch): change this to "/mirrors_test.dart" when
       // dart2js_mirrors_test.dart has been removed.
       (Uri uri) => uri.path.endsWith('mirrors_test.dart'));
   });
   test("Test dart library uri", () {
     testLibraryUri("test",
                    (Uri uri) {
                      if (uri == Uri.parse('dart:core')) return true;
                      // TODO(floitsch): do we want to fake the interceptors to
                      // be in dart:core?
                      return (uri == Uri.parse('dart:_interceptors'));
                    });
   });
   test("Test simple and qualifiedName", () { testNames(mirrors); });
   test("Test reflect type", () { testReflectClass(mirrors); });
 }