Revert "Change 502 response with no bypass info to block-once"

This reverts commit 452c35d1.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Change 502 response with no bypass info to block-once
> 
> CORB failures could block any response headers being sent to the rendere. These
> are treated as a random 1-5 minute bypass, since Chrome-Proxy is not in the
> response. This CL changes those bypasses to a block-once.
> 
> Bug: 947736
> Change-Id: I83c6a9874ccb26e4f17d8dccf7e9eeac8dd7f535
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1546678
> Commit-Queue: rajendrant <rajendrant@chromium.org>
> Reviewed-by: Tarun Bansal <tbansal@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#646136}

TBR=tbansal@chromium.org,rajendrant@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 947736
Change-Id: Ie2fafbf28cb2549d3e4b0d056b420af198dd5cb7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1546886Reviewed-by: rajendrant <rajendrant@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#646430}

chrome/browser/data_reduction_proxy/data_reduction_proxy_browsertest.cc

@@ -776,30 +776,6 @@ IN_PROC_BROWSER_TEST_F(DataReductionProxyFallbackBrowsertest,
                                       BYPASS_EVENT_TYPE_MALFORMED_407, 1);
 }
 
-IN_PROC_BROWSER_TEST_F(DataReductionProxyFallbackBrowsertest,
-                       ProxyBypassedForCurrentRequestOn502Error) {
-  base::HistogramTester histogram_tester;
-  net::EmbeddedTestServer test_server;
-  test_server.RegisterRequestHandler(
-      base::BindRepeating(&BasicResponse, kDummyBody));
-  ASSERT_TRUE(test_server.Start());
-
-  SetStatusCode(net::HTTP_BAD_GATEWAY);
-
-  ui_test_utils::NavigateToURL(browser(),
-                               GetURLWithMockHost(test_server, "/echo"));
-  EXPECT_THAT(GetBody(), kDummyBody);
-  histogram_tester.ExpectUniqueSample(
-      "DataReductionProxy.BlockTypePrimary",
-      BYPASS_EVENT_TYPE_STATUS_502_HTTP_BAD_GATEWAY, 1);
-
-  // Proxy should no longer be blocked, and use first proxy.
-  SetStatusCode(net::HTTP_OK);
-  ui_test_utils::NavigateToURL(browser(),
-                               GetURLWithMockHost(test_server, "/echo"));
-  EXPECT_EQ(GetBody(), kPrimaryResponse);
-}
-
 // Tests that if using data reduction proxy results in redirect loop, then
 // the proxy is bypassed, and the request is fetched directly.
 IN_PROC_BROWSER_TEST_F(DataReductionProxyFallbackBrowsertest, RedirectCycle) {

components/data_reduction_proxy/core/browser/data_reduction_proxy_bypass_stats_unittest.cc

@@ -473,22 +473,6 @@ TEST_F(DataReductionProxyBypassStatsEndToEndTest,
       histogram_tester, "DataReductionProxy.BypassedBytes.ProxyOverridden");
 }
 
-TEST_F(DataReductionProxyBypassStatsEndToEndTest, NoChromeProxy502AreBypassed) {
-  InitializeContext();
-  base::HistogramTester histogram_tester;
-  CreateAndExecuteRequest(GURL("http://foo.com"), net::LOAD_NORMAL, net::OK,
-                          "HTTP/1.1 502 Bad Gateway\r\n"
-                          "Via: 1.1 Chrome-Compression-Proxy\r\n"
-                          "Chrome-Proxy: block-once\r\n\r\n",
-                          kErrorBody.c_str(), "HTTP/1.1 200 OK\r\n\r\n",
-                          kBody.c_str());
-
-  histogram_tester.ExpectUniqueSample(
-      "DataReductionProxy.BypassedBytes.Current", kBody.size(), 1);
-  ExpectOtherBypassedBytesHistogramsEmpty(
-      histogram_tester, "DataReductionProxy.BypassedBytes.Current");
-}
-
 TEST_F(DataReductionProxyBypassStatsEndToEndTest, BypassedBytesCurrent) {
   InitializeContext();
   struct TestCase {
@@ -626,6 +610,9 @@ TEST_F(DataReductionProxyBypassStatsEndToEndTest,
     { "DataReductionProxy.BypassedBytes.Status500HttpInternalServerError",
       "HTTP/1.1 500 Internal Server Error\r\n\r\n",
     },
+    { "DataReductionProxy.BypassedBytes.Status502HttpBadGateway",
+      "HTTP/1.1 502 Bad Gateway\r\n\r\n",
+    },
     { "DataReductionProxy.BypassedBytes.Status503HttpServiceUnavailable",
       "HTTP/1.1 503 Service Unavailable\r\n\r\n",
     },

components/data_reduction_proxy/core/common/data_reduction_proxy_features.cc

@@ -46,10 +46,5 @@ const base::Feature kDataReductionProxyEnabledWithNetworkService{
     "DataReductionProxyEnabledWithNetworkService",
     base::FEATURE_DISABLED_BY_DEFAULT};
 
-// Enables block-once action when 502 is received with no Chrome-Proxy header.
-const base::Feature kDataReductionProxyBlockOnceOnBadGatewayResponse{
-    "DataReductionProxyBlockOnceOnBadGatewayResponse",
-    base::FEATURE_ENABLED_BY_DEFAULT};
-
 }  // namespace features
 }  // namespace data_reduction_proxy

components/data_reduction_proxy/core/common/data_reduction_proxy_features.h

@@ -17,7 +17,6 @@ extern const base::Feature kDogfood;
 extern const base::Feature kDataSaverSiteBreakdownUsingPageLoadMetrics;
 extern const base::Feature kDataReductionProxyEnabledWithNetworkService;
 extern const base::Feature kDataSaverUseOnDeviceSafeBrowsing;
-extern const base::Feature kDataReductionProxyBlockOnceOnBadGatewayResponse;
 
 }  // namespace features
 }  // namespace data_reduction_proxy

components/data_reduction_proxy/core/common/data_reduction_proxy_headers.cc

@@ -418,16 +418,8 @@ DataReductionProxyBypassType GetDataReductionProxyBypassType(
   // Fall back if a 500, 502 or 503 is returned.
   if (headers.response_code() == net::HTTP_INTERNAL_SERVER_ERROR)
     return BYPASS_EVENT_TYPE_STATUS_500_HTTP_INTERNAL_SERVER_ERROR;
-  if (headers.response_code() == net::HTTP_BAD_GATEWAY) {
-    if (base::FeatureList::IsEnabled(
-            features::kDataReductionProxyBlockOnceOnBadGatewayResponse)) {
-      data_reduction_proxy_info->bypass_all = true;
-      data_reduction_proxy_info->mark_proxies_as_bad = false;
-      data_reduction_proxy_info->bypass_duration = base::TimeDelta();
-      data_reduction_proxy_info->bypass_action = BYPASS_ACTION_TYPE_BLOCK_ONCE;
-    }
+  if (headers.response_code() == net::HTTP_BAD_GATEWAY)
     return BYPASS_EVENT_TYPE_STATUS_502_HTTP_BAD_GATEWAY;
-  }
   if (headers.response_code() == net::HTTP_SERVICE_UNAVAILABLE)
     return BYPASS_EVENT_TYPE_STATUS_503_HTTP_SERVICE_UNAVAILABLE;
   // TODO(kundaji): Bypass if Proxy-Authenticate header value cannot be