Remove Collection, Collections and clean up List/Set/Queue implementations of retain/remove.

pkg/args/lib/args.dart

Index: pkg/args/lib/args.dart
diff --git a/pkg/args/lib/args.dart b/pkg/args/lib/args.dart
index 48cef1642ece730acba2bbc42027c05a910255b0..5fe5c8b8cad28947b1c1c2cfe206f910e205bed7 100644
--- a/pkg/args/lib/args.dart
+++ b/pkg/args/lib/args.dart
@@ -417,7 +417,7 @@ class ArgResults {
     return _options[name];
   }
 
-  /** Get the names of the options as a [Collection]. */
-  Collection<String> get options => _options.keys.toList(growable: false);
+  /** Get the names of the options as an [Iterable]. */
+  Iterable<String> get options => _options.keys.toList(growable: false);

[nweiz, 2013/04/11 20:36:19]

If you're returning this as an Iterable, you can just return _options.keys.

[Anders Johnsen, 2013/04/12 09:31:14]

Done.

 }