Domain Reliability: Histogram net error codes from uploads

BUG=

Review URL: https://codereview.chromium.org/694573003

Cr-Commit-Position: refs/heads/master@{#302351}

components/domain_reliability/uploader.cc

@@ -11,6 +11,7 @@
 #include "base/stl_util.h"
 #include "base/supports_user_data.h"
 #include "net/base/load_flags.h"
+#include "net/base/net_errors.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
@@ -93,13 +94,36 @@ class DomainReliabilityUploaderImpl
     UploadCallbackMap::iterator callback_it = upload_callbacks_.find(fetcher);
     DCHECK(callback_it != upload_callbacks_.end());
 
-    VLOG(1) << "Upload finished with " << fetcher->GetResponseCode();
+    int net_error;
+    {
+      const net::URLRequestStatus& status = fetcher->GetStatus();
+      switch (status.status()) {
+        case net::URLRequestStatus::SUCCESS:
+          net_error = net::OK;
+          break;
+        case net::URLRequestStatus::CANCELED:
+          net_error = net::ERR_ABORTED;
+          break;
+        case net::URLRequestStatus::FAILED:
+          net_error = status.error();
+          break;
+        default:
+          NOTREACHED();
+          net_error = net::ERR_FAILED;
+          break;
+      }
+    }
+    int http_response_code = fetcher->GetResponseCode();
+
+    VLOG(1) << "Upload finished with net error " << net_error <<
+               " and HTTP response code " << http_response_code;
 
     UMA_HISTOGRAM_SPARSE_SLOWLY("DomainReliability.UploadResponseCode",
-                                fetcher->GetResponseCode());
+                                http_response_code);
+    UMA_HISTOGRAM_SPARSE_SLOWLY("DomainReliability.UploadNetError",
+                                -net_error);
 
-    bool success = fetcher->GetResponseCode() == 200;
-    callback_it->second.Run(success);
+    callback_it->second.Run(http_response_code == 200);
 
     delete callback_it->first;
     upload_callbacks_.erase(callback_it);

tools/metrics/histograms/histograms.xml

@@ -5219,11 +5219,19 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
-<histogram name="DomainReliability.UploadResponseCode">
+<histogram name="DomainReliability.UploadNetError" enum="NetErrorCodes">
   <owner>ttuttle@chromium.org</owner>
   <summary>
-    The response code returned by the Domain Reliability collector when a report
-    is uploaded.
+    The network error code (or OK if none) returned by the URLFetcher when a
+    Domain Reliability report is uploaded.
+  </summary>
+</histogram>
+
+<histogram name="DomainReliability.UploadResponseCode" enum="HttpResponseCode">
+  <owner>ttuttle@chromium.org</owner>
+  <summary>
+    The HTTP response code returned by the Domain Reliability collector when a
+    report is uploaded.
   </summary>
 </histogram>