Clean up directory listing interface.

runtime/bin/directory.h

Index: runtime/bin/directory.h
diff --git a/runtime/bin/directory.h b/runtime/bin/directory.h
index a187d69d80eec9b23d306eaa7648706f6c87d09d..0c6b7e23c4f1c2d9d6bb6260c423af12b6a0ea06 100644
--- a/runtime/bin/directory.h
+++ b/runtime/bin/directory.h
@@ -10,15 +10,12 @@
 
 class Directory {
  public:
-  static bool Open(const char* path, intptr_t* dir);
-  static bool Close(intptr_t dir);
   static void List(const char* path,
-                   intptr_t dir,
                    bool recursive,
-                   Dart_Port dir_handler,
-                   Dart_Port file_handler,
-                   Dart_Port done_handler,
-                   Dart_Port dir_error_handler);
+                   Dart_Port dir_port,
+                   Dart_Port file_port,
+                   Dart_Port done_port,
+                   Dart_Port error_port);
 
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(Directory);