Fixing flaky integration test

tools/chrome_proxy/webdriver/bypass.py

Index: tools/chrome_proxy/webdriver/bypass.py
diff --git a/tools/chrome_proxy/webdriver/bypass.py b/tools/chrome_proxy/webdriver/bypass.py
index e046ce74bf3d32bc48da13cb687973f78c03a86b..7eb98e1c51a92a945893c53d12c5862b2dbe468c 100644
--- a/tools/chrome_proxy/webdriver/bypass.py
+++ b/tools/chrome_proxy/webdriver/bypass.py
@@ -126,14 +126,17 @@ class Bypass(IntegrationTest):
         self.assertNotHasChromeProxyViaHeader(response)
         self.assertEqual(u'http/1.1', response.protocol)
 
-      # Check that the BlockTypePrimary histogram has a single entry in the
+      # Check that the BlockTypePrimary histogram has at least one entry in the
       # MissingViaHeader4xx category (which is enum value 4), to make sure that
       # the bypass was caused by the missing via header logic and not something
-      # else.
+      # else. The favicon for this URL may also be fetched, but will return a
+      # 404.
       histogram = test_driver.GetHistogram(
           "DataReductionProxy.BlockTypePrimary")
-      self.assertEqual(1, histogram['count'])
-      self.assertIn({'count': 1, 'high': 5, 'low': 4}, histogram['buckets'])
+      self.assertNotEqual(0, histogram['count'])
+      self.assertEqual(1, len(histogram['buckets']))
+      self.assertEqual(5, histogram['buckets'][0]['high'])
+      self.assertEqual(4, histogram['buckets'][0]['low'])
 
   # Verify that the Data Reduction Proxy understands the "exp" directive.
   def testExpDirectiveBypass(self):
@@ -191,4 +194,4 @@ class Bypass(IntegrationTest):
         self.assertEqual(80, response.port)        
 
 if __name__ == '__main__':
-  IntegrationTest.RunAllTests()
+  IntegrationTest.RunAllTests()