Make isEmpty a getter.

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 21 matching lines @@
 
   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 =>
-    name == null && version == Version.none && dependencies.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 103 matching lines @@
 
       if (parsedPubspec.containsKey('author')) {
         throw new FormatException('A pubspec should not have both an "author" '
             'and an "authors" field.');
       }
     }
 
     return new Pubspec(name, version, dependencies);
   }
 }