Fix up certificate error reporting histograms

net/http/transport_security_state_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "net/http/transport_security_state.h"
 
 #include <algorithm>
 #include <string>
 #include <vector>
 
@@ skipping 1369 matching lines @@
 
   std::string failure_log;
   EXPECT_EQ(TransportSecurityState::PKPStatus::VIOLATED,
             state.CheckPublicKeyPins(
                 host_port_pair, true, bad_hashes, cert1.get(), cert2.get(),
                 TransportSecurityState::ENABLE_PIN_REPORTS, &failure_log));
 
   // Check that the UMA histogram was updated when the report failed to
   // send.
   histograms.ExpectTotalCount(histogram_name, 1);
-  histograms.ExpectBucketCount(histogram_name, mock_report_sender.net_error(),
+  histograms.ExpectBucketCount(histogram_name, -mock_report_sender.net_error(),
                                1);
 }
 
 TEST_F(TransportSecurityStateTest, HPKPReportOnly) {
   HostPortPair host_port_pair(kHost, kPort);
   GURL report_uri(kReportUri);
   // Two dummy certs to use as the server-sent and validated chains. The
   // contents don't matter.
   scoped_refptr<X509Certificate> cert1 =
       ImportCertFromFile(GetTestCertsDirectory(), "test_mail_google_com.pem");
@@ skipping 548 matching lines @@
     EXPECT_EQ(original_status,
               state.ShouldRequireCT("www.example.com", cert.get(), hashes));
 
     state.SetRequireCTDelegate(nullptr);
     EXPECT_EQ(original_status,
               state.ShouldRequireCT("www.example.com", cert.get(), hashes));
   }
 }
 
 }  // namespace net