Integration test for Lo-Fi directives in the Chrome-Proxy response header

tools/chrome_proxy/common/chrome_proxy_metrics.py

 # Copyright 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.
 
 import logging
 import time
 
 from common import network_metrics
 from telemetry.page import page_test
 from telemetry.value import scalar
@@ skipping 60 matching lines @@
       return None
 
     chrome_proxy_request_header = self.response.request_headers['Chrome-Proxy']
     values = [v.strip() for v in chrome_proxy_request_header.split(',')]
     for value in values:
       kvp = value.split('=', 1)
       if len(kvp) == 2 and kvp[0].strip() == 'c':
         return kvp[1].strip()
     return None
 
-  def HasChromeProxyLoFi(self):
+  def HasChromeProxyLoFiRequest(self):
     if 'Chrome-Proxy' not in self.response.request_headers:
       return False
     chrome_proxy_request_header = self.response.request_headers['Chrome-Proxy']
     values = [v.strip() for v in chrome_proxy_request_header.split(',')]
-    for value in values:
-      if len(value) == 5 and value == 'q=low':
-        return True
-    return False
+    return any(v == "q=low" for v in values)
+
+  def HasChromeProxyLoFiResponse(self):
+    chrome_proxy_response_header = self.response.GetHeader('Chrome-Proxy')
+    if not chrome_proxy_response_header:
+      return False
+    values = [v.strip() for v in chrome_proxy_response_header.split(',')]
+    return any(v == "q=low" for v in values)