Land incremental building of the editor

dart/editor/build/truncate_files.py

Index: dart/editor/build/truncate_files.py
===================================================================
--- dart/editor/build/truncate_files.py	(revision 0)
+++ dart/editor/build/truncate_files.py	(revision 0)
@@ -0,0 +1,16 @@
+# Copyright (c) 2013, 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.
+
+import sys
+import os
+
+def main(args):
+  for file_name in args[1:]:
+    dir_name = os.path.dirname(file_name)
+    if not os.path.exists(dir_name):
+      os.mkdir(dir_name)
+    open(file_name, 'w').close()
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))