Make layout test harness extensible with custom layout tests directory

third_party/WebKit/Tools/Scripts/run-inspector-tests

Index: third_party/WebKit/Tools/Scripts/run-inspector-tests
diff --git a/third_party/WebKit/Tools/Scripts/run-inspector-tests b/third_party/WebKit/Tools/Scripts/run-inspector-tests
new file mode 100755
index 0000000000000000000000000000000000000000..1fb4d719513b20a3a1c822ecfe05d33e44b865d0
--- /dev/null
+++ b/third_party/WebKit/Tools/Scripts/run-inspector-tests
@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+# 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.
+
+"""Run inspector (DevTools) layout tests"""
+from os import path
+import sys
+
+from webkitpy.common import multiprocessing_bootstrap
+
+up = path.dirname
+layout_tests = path.join(up(up(up(path.abspath(__file__)))), 'Source', 'devtools', 'layout_tests')
+sys.argv.append('--layout-tests-directory={}'.format(layout_tests))
+multiprocessing_bootstrap.run('webkitpy', 'layout_tests', 'run_webkit_tests.py')