Migrate dartium_tools from chrome branch to dart repo

tools/dartium/update_patched_files.py

+#!/usr/bin/env python
+#
+# Copyright 2012 Google Inc. All Rights Reserved.
+
+import overrides_database
+import shutil
+import subprocess
+import sys
+
+
+def svn_update(path, rev):
+  subprocess.call(['svn', 'up', '-r', str(rev), path])
+
+
+def update_overridden_files(old_rev, new_rev):
+  assert old_rev < new_rev
+  for override in overrides_database.OVERRIDDEN_FILES:
+    patched = override['modified']
+    orig = override['original']
+    svn_update(orig, old_rev)
+    shutil.copyfile(patched, orig)
+    svn_update(orig, new_rev)
+    shutil.copyfile(orig, patched)
+
+
+if __name__ == '__main__':
+  update_overridden_files(int(sys.argv[1]), int(sys.argv[2]))