Add a Pub validator for READMEs that are invalid utf-8.

utils/pub/validator.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 validator;
 
 import 'dart:async';
 
 import 'entrypoint.dart';
 import 'log.dart' as log;
 import 'io.dart';
 import 'system_cache.dart';
 import 'utils.dart';
 import 'validator/dependency.dart';
 import 'validator/directory.dart';
 import 'validator/lib.dart';
 import 'validator/license.dart';
 import 'validator/name.dart';
 import 'validator/pubspec_field.dart';
+import 'validator/utf8_readme.dart';
 
 /// The base class for validators that check whether a package is fit for
 /// uploading. Each validator should override [errors], [warnings], or both to
 /// return lists of errors or warnings to display to the user. Errors will cause
 /// the package not to be uploaded; warnings will require the user to confirm
 /// the upload.
 abstract class Validator {
   /// The entrypoint that's being validated.
   final Entrypoint entrypoint;
 
@@ skipping 13 matching lines @@
   /// The future will complete with the error and warning messages,
   /// respectively.
   static Future<Pair<List<String>, List<String>>> runAll(
       Entrypoint entrypoint) {
     var validators = [
       new LibValidator(entrypoint),
       new LicenseValidator(entrypoint),
       new NameValidator(entrypoint),
       new PubspecFieldValidator(entrypoint),
       new DependencyValidator(entrypoint),
-      new DirectoryValidator(entrypoint)
+      new DirectoryValidator(entrypoint),
+      new Utf8ReadmeValidator(entrypoint)
     ];
 
     return Future.wait(validators.mappedBy((validator) => validator.validate()))
       .then((_) {
       var errors =
           flatten(validators.mappedBy((validator) => validator.errors));
       var warnings =
           flatten(validators.mappedBy((validator) => validator.warnings));
 
       if (!errors.isEmpty) {
         log.error("Missing requirements:");
         for (var error in errors) {
           log.error("* ${Strings.join(error.split('\n'), '\n  ')}");
         }
         log.error("");
       }
 
       if (!warnings.isEmpty) {
         log.warning("Suggestions:");
         for (var warning in warnings) {
           log.warning("* ${Strings.join(warning.split('\n'), '\n  ')}");
         }
         log.warning("");
       }
 
       return new Pair<List<String>, List<String>>(errors, warnings);
     });
   }
 }