Use new common tools in Python scripts

tools/fix_pythonpath.py

Index: tools/fix_pythonpath.py
diff --git a/tools/fix_pythonpath.py b/tools/fix_pythonpath.py
new file mode 100644
index 0000000000000000000000000000000000000000..dfd1b480e10cd21dd68f585c431a28f11ef3eddb
--- /dev/null
+++ b/tools/fix_pythonpath.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+# Copyright (c) 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+"""Add commonly-used directories to PYTHONPATH."""

[rmistry, 2014/06/25 13:56:22]

The problem with this module determining which directories need to be added to
the pythonpath of all calling modules is that it may result in conflicts or the
import of an unintended module.

Having only the checkout root added automatically, makes it very obvious what is
going on instead of not knowing which directories are going to be magically
added.

I assume we will want to do something similar in the other two repositories in
which case we should come up with a solution for a generic "fix_pythonpath"
module here.

If we want this module to support more directories than the checkout root then
an explicit way of doing this is to add a function here that has the signature
'def append_to_pythonpath(dirs)'
Clients would invoke it with constants defined in this file:
fix_pythonpath.append_to_pythonpath(fix_pythonpath.CHECKOUT_ROOT,
fix_pythonpath.SKIA_SITE_CONFIG_DIR)

or maybe CHECKOUT_ROOT is always added to the pythonpath like you currently
have, and the append_to_pythonpath function will be used only for additional
dirs that callers care about.

[borenet, 2014/06/25 14:53:32]

I think the last idea sounds best to me: automatically add the checkout root,
provide easy mechanisms for adding others.

+
+
+import os
+import sys
+
+
+CHECKOUT_ROOT = os.path.realpath(os.path.join(
+    os.path.dirname(os.path.abspath(__file__)), os.pardir))
+sys.path.insert(0, CHECKOUT_ROOT)
+
+
+if __name__ == '__main__':
+  print 'PYTHONPATH=%s' % ':'.join(sys.path)