Add a run_eslint wrapper script

common/eslint/eslint/__init__.py

Index: common/eslint/eslint/__init__.py
diff --git a/common/eslint/eslint/__init__.py b/common/eslint/eslint/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..bd6c184c766d30ccfd2eabeb9f6aa1ea768207db
--- /dev/null
+++ b/common/eslint/eslint/__init__.py
@@ -0,0 +1,24 @@
+# Copyright 2016 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.
+
+import os
+import sys
+
+
+_CATAPULT_PATH = os.path.join(
+    os.path.dirname(os.path.abspath(__file__)),
+    os.path.pardir, os.path.pardir, os.path.pardir)
+
+
+def _AddToPathIfNeeded(path):
+  if path not in sys.path:
+    sys.path.insert(0, path)
+
+
+def _UpdateSysPathIfNeeded():
+  _AddToPathIfNeeded(os.path.join(_CATAPULT_PATH, 'common', 'node_runner'))
+  _AddToPathIfNeeded(os.path.join(_CATAPULT_PATH, 'common', 'py_utils'))
+
+
+_UpdateSysPathIfNeeded()