Measure network error rates with and without data reduction proxy

chrome/browser/net/chrome_network_delegate.cc

Index: chrome/browser/net/chrome_network_delegate.cc
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index ae84c3eb7eb7b887cbf8ad2baf8febf69a305fa7..b892db9abd6c93f218d9dce2aa5c0ab9b766e0cd 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -15,6 +15,7 @@
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/metrics/user_metrics.h"
 #include "base/path_service.h"
 #include "base/prefs/pref_member.h"
@@ -243,6 +244,27 @@ void ReportInvalidReferrerSend(const GURL& target_url,
   NOTREACHED();
 }
 
+// Determine whether the specified |request| is for a main frame resource. Used
+// for histograms.
+bool IsMainFrameResourceRequest(const net::URLRequest* request) {
+  const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request);
+  return info && info->GetResourceType() == content::RESOURCE_TYPE_MAIN_FRAME;
+}
+
+// Record network errors that requests complete with, including OK and ABORTED.
+void RecordNetworkErrorHistograms(const net::URLRequest* request) {
+  if (request->url().SchemeIs("http")) {
+    UMA_HISTOGRAM_SPARSE_SLOWLY("Net.HttpRequestCompletionErrorCodes",
+                                std::abs(request->status().error()));
+
+    if (IsMainFrameResourceRequest(request)) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY(
+          "Net.HttpRequestCompletionErrorCodes.MainFrame",
+          std::abs(request->status().error()));
+    }
+  }
+}
+
 }  // namespace
 
 ChromeNetworkDelegate::ChromeNetworkDelegate(
@@ -549,7 +571,10 @@ void ChromeNetworkDelegate::OnRawBytesRead(const net::URLRequest& request,
 void ChromeNetworkDelegate::OnCompleted(net::URLRequest* request,
                                         bool started) {
   if (data_reduction_proxy_usage_stats_)
-    data_reduction_proxy_usage_stats_->OnUrlRequestCompleted(request, started);
+    data_reduction_proxy_usage_stats_->OnUrlRequestCompleted(

[bengr, 2014/12/09 23:44:13]

After megjablon@'s CL lands, this will be in DataReductionProxyNetworkDelegate.
Note that this, unlike ChromeNetworkDelegate, cannot depend on content.

[sclittle, 2014/12/10 00:05:03]

Darn. Being able to single out main frame resource loads from other requests
using the Net.ErrorCodesForMainFrame3 histogram has helped identify net errors
that are likely a problem for the DRP, so having them singled out here could be
quite helpful as well. There must be a way to plumb this information through,
even if it requires injecting a callback, or putting some stuff in
components/data_reduction_proxy/content.

How close is megjablon@'s CL to landing? Should I hold off on this CL so that
they can be integrated together more nicely?

+        request, started, IsMainFrameResourceRequest(request));
+
+  RecordNetworkErrorHistograms(request);
 
   TRACE_EVENT_ASYNC_END0("net", "URLRequest", request);
   if (request->status().status() == net::URLRequestStatus::SUCCESS) {