Move chrome/browser/web_dev_style/ to tools/ to use from more places

tools/web_dev_style/css_checker_test.py

 #!/usr/bin/env python
 # Copyright 2015 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 css_checker
 from os import path as os_path
 import re
 from sys import path as sys_path
 import unittest
 
 _HERE = os_path.dirname(os_path.abspath(__file__))
-sys_path.append(os_path.join(_HERE, '..', '..', '..', 'build'))
+sys_path.append(os_path.join(_HERE, '..', '..', 'build'))
 
 import find_depot_tools  # pylint: disable=W0611
 from testing_support.super_mox import SuperMoxTestBase
 
 
 class CssCheckerTest(SuperMoxTestBase):
   def setUp(self):
     SuperMoxTestBase.setUp(self)
 
     self.fake_file = self.mox.CreateMockAnything()
@@ skipping 484 matching lines @@
   </style>
 </head>
 </html>""", """
 - Colons (:) should have a space after them.
     flex-direction:column;
 """, filename='test.html')
 
 
 if __name__ == '__main__':
   unittest.main()