Added the continueParsing option to ArgParser.

sdk/lib/_internal/dartdoc/bin/dartdoc.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.
 
 /**
  * To generate docs for a library, run this script with the path to an
  * entrypoint .dart file, like:
  *
  *     $ dart dartdoc.dart foo.dart
  *
@@ skipping 162 matching lines @@
 
   if (args.isEmpty) {
     print('No arguments provided.');
     print(USAGE);
     print(argParser.getUsage());
     exit(1);
   }
 
   final entrypoints = <Path>[];
   try {
-    final option = argParser.parse(args);
+    final option = argParser.parse(args, continueParsing: true);
 
     // This checks to see if the root of all entrypoints is the same.
     // If it is not, then we display a warning, as package imports might fail.
     var entrypointRoot;
     for(final arg in option.rest) {
       var entrypoint = new Path(arg);
       entrypoints.add(entrypoint);
 
       if (entrypointRoot == null) {
         entrypointRoot = entrypoint.directoryPath;
@@ skipping 57 matching lines @@
               '${dartdoc.totalTypes} types, and ${dartdoc.totalMembers} '
               'members.');
       }
     });
   }, onError: (AsyncError asyncError) {
     print('Generation failed: ${asyncError.error}');
     dartdoc.cleanup();
     exit(1);
   });
 }