Add an entry in histograms.xml for SafeBrowsing.V4UpdateHttpResponseOrErrorCode

components/safe_browsing_db/v4_update_protocol_manager.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 "components/safe_browsing_db/v4_update_protocol_manager.h"
 
 #include <utility>
 
 #include "base/base64.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/rand_util.h"
 #include "base/timer/timer.h"
 #include "components/safe_browsing_db/safebrowsing.pb.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_context_getter.h"
 
 using base::Time;
@@ skipping 299 matching lines @@
     // The callback must call ScheduleNextUpdate() at the end to resume
     // downloading updates.
     update_callback_.Run(list_update_responses);
   } else {
     DVLOG(1) << "SafeBrowsing GetEncodedUpdates request for: "
              << source->GetURL() << " failed with error: " << status.error()
              << " and response code: " << response_code;
 
     if (status.status() == net::URLRequestStatus::FAILED) {
       RecordUpdateResult(V4OperationResult::NETWORK_ERROR);
+      // Negate the error value since it is negative, see:
+      // net/base/net_error_list.h
+      UMA_HISTOGRAM_SPARSE_SLOWLY("SafeBrowsing.V4UpdateNetworkError",

[Nathan Parker, 2016/06/02 20:56:31]

How about recording both the network error or status, like
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/saf...

[vakh (use Gerrit instead), 2016/06/02 21:43:27]

Done.

+                                  -status.error());
     } else {
       RecordUpdateResult(V4OperationResult::HTTP_ERROR);
     }
     // TODO(vakh): Figure out whether it is just a network error vs backoff vs
     // another condition and RecordUpdateResult more accurately.
 
     request_.reset();
     ScheduleNextUpdateWithBackoff(true);
   }
 }
 
 GURL V4UpdateProtocolManager::GetUpdateUrl(
     const std::string& req_base64) const {
   GURL url = V4ProtocolManagerUtil::GetRequestUrl(req_base64, "encodedUpdates",
                                                   config_);
   DVLOG(1) << "V4UpdateProtocolManager::GetUpdateUrl: "
            << "url: " << url;
   return url;
 }
 
 }  // namespace safe_browsing