Split dart:builtin into dart:builtin and dart:io.

frog/leg/scanner/vm_scanner_bench.dart

Index: frog/leg/scanner/vm_scanner_bench.dart
diff --git a/frog/leg/scanner/vm_scanner_bench.dart b/frog/leg/scanner/vm_scanner_bench.dart
index 24e7e35d53f2c565aa4c4f86f7a0389529353c47..5064eb2003024cd63ca6ce5236fe8a1cf9d4c213 100644
--- a/frog/leg/scanner/vm_scanner_bench.dart
+++ b/frog/leg/scanner/vm_scanner_bench.dart
@@ -1,8 +1,9 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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('vm_scanner_bench');
+#import('dart:io');
 #import('scannerlib.dart');
 #import('scanner_implementation.dart');
 #import('scanner_bench.dart');