Update experiment test to only verify /exptest/... are bypassed

tools/chrome_proxy/integration_tests/chrome_proxy_measurements.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 base64
 import logging
 import urlparse
 
 from common.chrome_proxy_measurements import ChromeProxyValidation
 from integration_tests import chrome_proxy_metrics as metrics
@@ skipping 274 matching lines @@
   def __init__(self):
     super(ChromeProxyExpDirective, self).__init__(
         restart_after_each_page=True,
         metrics=metrics.ChromeProxyMetric())
 
   def CustomizeBrowserOptions(self, options):
     super(ChromeProxyExpDirective, self).CustomizeBrowserOptions(options)
     options.AppendExtraBrowserArgs('--data-reduction-proxy-experiment=test')
 
   def AddResults(self, tab, results):
-    self._metrics.AddResultsForBypass(tab, results)
+    self._metrics.AddResultsForBypass(tab, results, url_pattern='/exptest/')
 
 
 class ChromeProxyHTTPToDirectFallback(ChromeProxyValidation):
   """Correctness measurement for HTTP proxy fallback to direct."""
 
   def __init__(self):
     super(ChromeProxyHTTPToDirectFallback, self).__init__(
         restart_after_each_page=True,
         metrics=metrics.ChromeProxyMetric())
 
@@ skipping 63 matching lines @@
             self._metrics.AddResultsForDataSaving,
             ],
         'bypass': [self._metrics.AddResultsForBypass],
         }
     if not self._page.name in page_to_metrics:
       raise page_test.MeasurementFailure(
           'Invalid page name (%s) in smoke. Page name must be one of:\n%s' % (
           self._page.name, page_to_metrics.keys()))
     for add_result in page_to_metrics[self._page.name]:
       add_result(tab, results)