Fix some compilation errors and warnings in Pub.

utils/pub/pubspec.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('pubspec');
 
 #import('package.dart');
 #import('source.dart');
 #import('source_registry.dart');
 #import('utils.dart');
@@ skipping 20 matching lines @@
   List<PackageRef> dependencies;
 
   Pubspec(this.name, this.version, this.dependencies);
 
   Pubspec.empty()
     : name = null,
       version = Version.none,
       dependencies = <PackageRef>[];
 
   /** Whether or not the pubspec has no contents. */
-  bool get isEmpty() =>
+  bool get isEmpty =>
     name == null && version == Version.none && dependencies.isEmpty();
 
   /**
    * Parses the pubspec whose text is [contents]. If the pubspec doesn't define
    * version for itself, it defaults to [Version.none].
    */
   factory Pubspec.parse(String contents, SourceRegistry sources) {
     var name = null;
     var version = Version.none;
     var dependencies = <PackageRef>[];
@@ skipping 66 matching lines @@
         }
 
         dependencies.add(new PackageRef(
             source, versionConstraint, description));
       });
     }
 
     return new Pubspec(name, version, dependencies);
   }
 }