Fix up certificate error reporting histograms

chrome/browser/ssl/chrome_expect_ct_reporter_unittest.cc

 // Copyright 2016 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 "chrome/browser/ssl/chrome_expect_ct_reporter.h"
 
 #include <string>
 
 #include "base/base64.h"
 #include "base/command_line.h"
@@ skipping 381 matching lines @@
       net::GetTestCertsDirectory(), "localhost_cert.pem");
 
   net::HostPortPair host_port("example.test", 443);
   GURL report_uri(
       net::URLRequestFailedJob::GetMockHttpUrl(net::ERR_CONNECTION_FAILED));
 
   SendReport(&reporter, host_port, report_uri, ssl_info);
 
   histograms.ExpectTotalCount(kFailureHistogramName, 1);
   histograms.ExpectBucketCount(kFailureHistogramName,
-                               net::ERR_CONNECTION_FAILED, 1);
+                               -net::ERR_CONNECTION_FAILED, 1);
   histograms.ExpectTotalCount(kSendHistogramName, 1);
   histograms.ExpectBucketCount(kSendHistogramName, true, 1);
 }
 
 // Test that a sent report has the right format.
 TEST(ChromeExpectCTReporterTest, SendReport) {
   base::HistogramTester histograms;
   histograms.ExpectTotalCount(kFailureHistogramName, 0);
   histograms.ExpectTotalCount(kSendHistogramName, 0);
 
@@ skipping 50 matching lines @@
   reporter.OnExpectCTFailed(host_port, report_uri, ssl_info);
   EXPECT_EQ(report_uri, sender->latest_report_uri());
   EXPECT_FALSE(sender->latest_serialized_report().empty());
   ASSERT_NO_FATAL_FAILURE(CheckExpectCTReport(
       sender->latest_serialized_report(), host_port, ssl_info));
 
   histograms.ExpectTotalCount(kFailureHistogramName, 0);
   histograms.ExpectTotalCount(kSendHistogramName, 1);
   histograms.ExpectBucketCount(kSendHistogramName, true, 1);
 }