Add action to copy chromedriver.

tools/copy_binary.py

@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+import os
+import shutil
+import stat
+import sys
+
+src = sys.argv[1]
+dist = sys.argv[2]
+
+shutil.copyfile(src, dist)
+os.chmod(dist, os.stat(dist).st_mode | stat.S_IEXEC)