Adds a repeatable --url_mapping flag to dartanalyzer

pkg/analyzer/test/options_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.
 
 library options_test;
 
 import 'package:analyzer/options.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
@@ skipping 12 matching lines @@
       expect(options.log, isFalse);
       expect(options.machineFormat, isFalse);
       expect(options.packageRootPath, isNull);
       expect(options.perf, isFalse);
       expect(options.shouldBatch, isFalse);
       expect(options.showPackageWarnings, isFalse);
       expect(options.showSdkWarnings, isFalse);
       expect(options.sourceFiles, equals(['foo.dart']));
       expect(options.warmPerf, isFalse);
       expect(options.warningsAreFatal, isFalse);
+      expect(options.customUrlMappings, isNotNull);
+      expect(options.customUrlMappings.isEmpty, isTrue);
     });
 
     test('batch', () {
       CommandLineOptions options =
           CommandLineOptions.parse(['--dart-sdk', '.', '--batch']);
       expect(options.shouldBatch, isTrue);
     });
 
     test('defined variables', () {
       CommandLineOptions options =
@@ skipping 57 matching lines @@
           options.sourceFiles,
           equals(['foo.dart', 'foo2.dart', 'foo3.dart']));
     });
 
     test('warningsAreFatal', () {
       CommandLineOptions options =
           CommandLineOptions.parse(['--dart-sdk', '.', '--fatal-warnings', 'foo.dart']);
       expect(options.warningsAreFatal, isTrue);
     });
 
+    test('customUrlMappings', () {
+      CommandLineOptions options = CommandLineOptions.parse([
+          '--dart-sdk', '.',
+          '--url_mapping', 'dart:dummy,/path/to/dummy.dart',
+          'foo.dart']);
+      expect(options.customUrlMappings, isNotNull);
+      expect(options.customUrlMappings.isEmpty, isFalse);
+      expect(options.customUrlMappings['dart:dummy'],
+             equals('/path/to/dummy.dart'));
+    });
+
 //    test('notice unrecognized flags', () {
 //      CommandLineOptions options = new CommandLineOptions.parse(['--bar', '--baz',
 //        'foo.dart']);
 //      expect(options, isNull);
 //    });
 //
 //    test('ignore unrecognized flags', () {
 //      CommandLineOptions options = new CommandLineOptions.parse([
 //        '--ignore_unrecognized_flags', '--bar', '--baz', 'foo.dart']);
 //      expect(options, isNotNull);
 //      expect(options.sourceFiles, equals(['foo.dart']));
 //    });
 
   });
 
 }