Fix errors when running against staging

tools/chrome_proxy/webdriver/common.py

 # 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 argparse
 import json
 import logging
 import os
 import re
 import socket
@@ skipping 543 matching lines @@
   unittest.TestCase class.
   """
 
   def assertHasChromeProxyViaHeader(self, http_response):
     """Asserts that the Via header in the given HTTPResponse matches the
     expected value as given on the command line.
 
     Args:
       http_response: The HTTPResponse object to check.
     """
+    self.assertIn('via', http_response.response_headers)
     expected_via_header = ParseFlags().via_header_value
-    self.assertIn('via', http_response.response_headers)
-    self.assertEqual(expected_via_header, http_response.response_headers['via'])
+    actual_via_headers = http_response.response_headers['via'].split(',')
+    self.assertIn(expected_via_header, actual_via_headers, "Via header not in "
+      "response headers! Expected: %s, Actual: %s" %
+      (expected_via_header, actual_via_headers))
 
   def assertNotHasChromeProxyViaHeader(self, http_response):
     """Asserts that the Via header in the given HTTPResponse does not match the
     expected value as given on the command line.
 
     Args:
       http_response: The HTTPResponse object to check.
     """
-    expected_via_header = ParseFlags().via_header_value
-    self.assertNotIn('via', http_response.response_headers)
     if 'via' in http_response.response_headers:
-      self.assertNotIn(expected_via_header,
-        http_response.response_headers['via'])
+      expected_via_header = ParseFlags().via_header_value
+      actual_via_headers = http_response.response_headers['via'].split(',')
+      self.assertNotIn(expected_via_header, actual_via_headers, "Via header "
+        "found in response headers! Not expected: %s, Actual: %s" %
+        (expected_via_header, actual_via_headers))
 
   def checkLoFiResponse(self, http_response, expected_lo_fi):
     """Asserts that if expected the response headers contain the Lo-Fi directive
     then the request headers do too. Also checks that the content size is less
     than 100 if |expected_lo_fi|. Otherwise, checks that the response and
     request headers don't contain the Lo-Fi directive and the content size is
     greater than 100.
 
     Args:
       http_response: The HTTPResponse object to check.
@@ skipping 141 matching lines @@
       args[0].skipTest('This test runs on Mac OS only.')
   return wrapper
 
 def NotMac(func):
   def wrapper(*args, **kwargs):
     if sys.platform == 'darwin':
       func(*args, **kwargs)
     else:
       args[0].skipTest('This test does not run on Mac OS.')
   return wrapper