Don't report DRP request error code UMA when LOAD_BYPASS_PROXY is set.

This fixes a reporting bug with the
DataReductionProxy.RequestCompletionErrorCodes histograms. Previously,
these histograms counted requests that encountered errors when retrying
the request after bypassing the data reduction proxy (e.g. block-once).
This is incorrect because the error did not occur when trying to use the
DRP.

The fix is to ignore requests that completed with the LOAD_BYPASS_PROXY
load flag, since these requests did not use the DRP even if the
proxy_server() in the URLRequest is still set to the DRP.

BUG=454947

Review URL: https://codereview.chromium.org/896793004

Cr-Commit-Position: refs/heads/master@{#314432}

components/data_reduction_proxy/core/browser/data_reduction_proxy_usage_stats.cc

@@ -128,8 +128,13 @@ void DataReductionProxyUsageStats::OnUrlRequestCompleted(
   DCHECK(thread_checker_.CalledOnValidThread());
 
   DataReductionProxyTypeInfo proxy_info;
+  // Ignore requests that did not use the data reduction proxy. The check for
+  // LOAD_BYPASS_PROXY is necessary because the proxy_server() in the |request|
+  // might still be set to the data reduction proxy if |request| was retried
+  // over direct and a network error occurred while retrying it.
   if (data_reduction_proxy_params_->WasDataReductionProxyUsed(request,
-                                                              &proxy_info)) {
+                                                              &proxy_info) &&
+      (request->load_flags() & net::LOAD_BYPASS_PROXY) == 0) {
     if (request->status().status() == net::URLRequestStatus::SUCCESS) {
       successful_requests_through_proxy_count_++;
       NotifyUnavailabilityIfChanged();

components/data_reduction_proxy/core/browser/data_reduction_proxy_usage_stats_unittest.cc

@@ -448,22 +448,25 @@ TEST_F(DataReductionProxyUsageStatsTest, RequestCompletionErrorCodes) {
 
   struct TestCase {
     bool was_proxy_used;
+    bool is_load_bypass_proxy;
     bool is_fallback;
     bool is_main_frame;
     net::Error net_error;
   };
 
   const TestCase test_cases[] = {
-    {false, false, true, net::OK},
-    {false, false, false, net::ERR_TOO_MANY_REDIRECTS},
-    {true, false, true, net::OK},
-    {true, false, true, net::ERR_TOO_MANY_REDIRECTS},
-    {true, false, false, net::OK},
-    {true, false, false, net::ERR_TOO_MANY_REDIRECTS},
-    {true, true, true, net::OK},
-    {true, true, true, net::ERR_TOO_MANY_REDIRECTS},
-    {true, true, false, net::OK},
-    {true, true, false, net::ERR_TOO_MANY_REDIRECTS}
+    {false, true, false, true, net::OK},
+    {false, true, false, false, net::ERR_TOO_MANY_REDIRECTS},
+    {false, false, false, true, net::OK},
+    {false, false, false, false, net::ERR_TOO_MANY_REDIRECTS},
+    {true, false, false, true, net::OK},
+    {true, false, false, true, net::ERR_TOO_MANY_REDIRECTS},
+    {true, false, false, false, net::OK},
+    {true, false, false, false, net::ERR_TOO_MANY_REDIRECTS},
+    {true, false, true, true, net::OK},
+    {true, false, true, true, net::ERR_TOO_MANY_REDIRECTS},
+    {true, false, true, false, net::OK},
+    {true, false, true, false, net::ERR_TOO_MANY_REDIRECTS}
   };
 
   for (size_t i = 0; i < arraysize(test_cases); ++i) {
@@ -478,6 +481,10 @@ TEST_F(DataReductionProxyUsageStatsTest, RequestCompletionErrorCodes) {
     scoped_ptr<net::URLRequest> fake_request(
         CreateURLRequestWithResponseHeaders(GURL("http://www.google.com/"),
                                             raw_headers));
+    if (test_cases[i].is_load_bypass_proxy) {
+      fake_request->SetLoadFlags(fake_request->load_flags() |
+                                 net::LOAD_BYPASS_PROXY);
+    }
     if (test_cases[i].is_main_frame) {
       fake_request->SetLoadFlags(fake_request->load_flags() |
                                  net::LOAD_MAIN_FRAME);
@@ -497,27 +504,29 @@ TEST_F(DataReductionProxyUsageStatsTest, RequestCompletionErrorCodes) {
 
     usage_stats->OnUrlRequestCompleted(fake_request.get(), false);
 
-    if (test_cases[i].was_proxy_used && !test_cases[i].is_fallback) {
+    if (test_cases[i].was_proxy_used && !test_cases[i].is_load_bypass_proxy &&
+        !test_cases[i].is_fallback) {
       histogram_tester.ExpectUniqueSample(
           kPrimaryHistogramName, -net_error_int, 1);
     } else {
       histogram_tester.ExpectTotalCount(kPrimaryHistogramName, 0);
     }
-    if (test_cases[i].was_proxy_used && test_cases[i].is_fallback) {
+    if (test_cases[i].was_proxy_used && !test_cases[i].is_load_bypass_proxy &&
+        test_cases[i].is_fallback) {
       histogram_tester.ExpectUniqueSample(
           kFallbackHistogramName, -net_error_int, 1);
     } else {
       histogram_tester.ExpectTotalCount(kFallbackHistogramName, 0);
     }
-    if (test_cases[i].was_proxy_used && !test_cases[i].is_fallback &&
-        test_cases[i].is_main_frame) {
+    if (test_cases[i].was_proxy_used && !test_cases[i].is_load_bypass_proxy &&
+        !test_cases[i].is_fallback && test_cases[i].is_main_frame) {
       histogram_tester.ExpectUniqueSample(
           kPrimaryMainFrameHistogramName, -net_error_int, 1);
     } else {
       histogram_tester.ExpectTotalCount(kPrimaryMainFrameHistogramName, 0);
     }
-    if (test_cases[i].was_proxy_used && test_cases[i].is_fallback &&
-        test_cases[i].is_main_frame) {
+    if (test_cases[i].was_proxy_used && !test_cases[i].is_load_bypass_proxy &&
+        test_cases[i].is_fallback && test_cases[i].is_main_frame) {
       histogram_tester.ExpectUniqueSample(
           kFallbackMainFrameHistogramName, -net_error_int, 1);
     } else {