Add detailed histograms for DownloadProtectionService URLFetcher errors.

chrome/browser/safe_browsing/download_protection_service.cc

Index: chrome/browser/safe_browsing/download_protection_service.cc
diff --git a/chrome/browser/safe_browsing/download_protection_service.cc b/chrome/browser/safe_browsing/download_protection_service.cc
index 2c5f5901c2a16f35211e953f68a0f5a351bfe2ab..6d75087c0ee69aed0f814ce3f3f4c5848fdaafb4 100644
--- a/chrome/browser/safe_browsing/download_protection_service.cc
+++ b/chrome/browser/safe_browsing/download_protection_service.cc
@@ -10,6 +10,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/sequenced_task_runner_helpers.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
@@ -388,6 +389,14 @@ class DownloadProtectionService::CheckClientDownloadRequest
             << item_->GetUrlChain().back() << ": success="
             << source->GetStatus().is_success() << " response_code="
             << source->GetResponseCode();
+    if (source->GetStatus().is_success()) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY(
+          "SBClientDownload.DownloadRequestResponseCode",
+          source->GetResponseCode());
+    }
+    UMA_HISTOGRAM_SPARSE_SLOWLY(
+        "SBClientDownload.DownloadRequestNetError",
+        -source->GetStatus().error());
     DownloadCheckResultReason reason = REASON_SERVER_PING_FAILED;
     DownloadCheckResult result = SAFE;
     if (source->GetStatus().is_success() &&