Adding a CORS bypass integration test

tools/chrome_proxy/webdriver/cors_bypass.py

+# Copyright 2017 The Chromium Authors. All rights reserved.

[megjablon, 2017/02/01 00:14:38]

The bug and spreadsheet said this should go in bypass.py. Robert, do we want
separate files for these or aggregated as you organized?

[RyanSturm, 2017/02/01 01:45:41]

Done.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import common
+from common import TestDriver
+from common import IntegrationTest
+
+
+class CorsBypass(IntegrationTest):
+
+  # Verify that CORS requests receive a block-once from the data reduction
+  # proxy by checking that those requests are retried without data reduction
+  # proxy.
+  def testCorsBypass(self):
+    with TestDriver() as test_driver:
+      test_driver.AddChromeArg('--enable-spdy-proxy-auth')
+      test_driver.LoadURL('http://www.gstatic.com/chrome/googlezip/cors/')
+
+      # Navigate to a different page to verify that later requests are not
+      # blocked.
+      test_driver.LoadURL('http://check.googlezip.net/test.html')
+
+      cors_requests = 0
+      same_origin_requests = 0
+      for response in test_driver.GetHTTPResponses():
+        # The origin header implies that |response| is a CORS request.
+        if ('origin' not in response.request_headers):
+          self.assertHasChromeProxyViaHeader(response)
+          same_origin_requests = same_origin_requests + 1
+        else:
+          self.assertNotHasChromeProxyViaHeader(response)
+          cors_requests = cors_requests + 1
+      # Verify that both CORS and same origin requests were seen.
+      self.assertNotEqual(0, same_origin_requests)
+      self.assertNotEqual(0, cors_requests)
+
+if __name__ == '__main__':
+  IntegrationTest.RunAllTests()