Integration test for Chrome-Proxy: pass-through directive

tools/chrome_proxy/integration_tests/chrome_proxy_pagesets/pass_through.py

+# 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.
+
+from telemetry.page import page as page_module
+from telemetry.page import page_set as page_set_module
+
+class PassThroughPage(page_module.Page):
+  """
+  A test page for the chrome proxy pass-through tests.
+  """
+
+  def __init__(self, url, page_set):
+    super(PassThroughPage, self).__init__(url=url, page_set=page_set)
+
+  def RunNavigateSteps(self, action_runner):
+    super(PassThroughPage, self).RunNavigateSteps(action_runner)
+    action_runner.ExecuteJavaScript('''
+        (function() {
+          var request = new XMLHttpRequest();
+          request.open("GET", "%s");
+          request.setRequestHeader("Chrome-Proxy", "pass-through");
+          request.send(null);
+        })();''' % (self.url))
+    action_runner.Wait(1)
+
+
+class PassThroughPageSet(page_set_module.PageSet):
+  """ Chrome proxy test sites """
+
+  def __init__(self):
+    super(PassThroughPageSet, self).__init__()
+
+    urls_list = [
+      'http://check.googlezip.net/image.png',
+    ]
+
+    for url in urls_list:
+      self.AddUserStory(PassThroughPage(url, self))