Adds feature flag for chrome-proxy-ect header (default off)

components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/time/time.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_bypass_stats.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_config.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_configurator.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_data.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_io_data.h"
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_request_options.h"
 #include "components/data_reduction_proxy/core/browser/data_use_group.h"
 #include "components/data_reduction_proxy/core/browser/data_use_group_provider.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_features.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_util.h"
 #include "components/data_reduction_proxy/core/common/lofi_decider.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_request_headers.h"
 #include "net/http/http_response_headers.h"
 #include "net/nqe/effective_connection_type.h"
 #include "net/nqe/network_quality_estimator.h"
 #include "net/proxy/proxy_info.h"
@@ skipping 83 matching lines @@
          util::CalculateEffectiveOCL(request);
 }
 
 // Verifies that the chrome proxy related request headers are set correctly.
 // |via_chrome_proxy| is true if the request is being fetched via Chrome Data
 // Saver proxy.
 void VerifyHttpRequestHeaders(bool via_chrome_proxy,
                               const net::HttpRequestHeaders& headers) {
   if (via_chrome_proxy) {
     DCHECK(headers.HasHeader(chrome_proxy_header()));
-    DCHECK(headers.HasHeader(chrome_proxy_ect_header()));
+    DCHECK_EQ(
+        data_reduction_proxy::features::IsDataReductionProxyECTHeaderEnabled(),
+        headers.HasHeader(chrome_proxy_ect_header()));
   } else {
     DCHECK(!headers.HasHeader(chrome_proxy_header()));
     DCHECK(!headers.HasHeader(chrome_proxy_accept_transform_header()));
     DCHECK(!headers.HasHeader(chrome_proxy_ect_header()));
   }
 }
 
 }  // namespace
 
 DataReductionProxyNetworkDelegate::DataReductionProxyNetworkDelegate(
@@ skipping 383 matching lines @@
   header_value += kBrotli;
   request_headers->SetHeader(net::HttpRequestHeaders::kAcceptEncoding,
                              header_value);
 }
 
 void DataReductionProxyNetworkDelegate::MaybeAddChromeProxyECTHeader(
     net::HttpRequestHeaders* request_headers,
     const net::URLRequest& request) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  if (!data_reduction_proxy::features::IsDataReductionProxyECTHeaderEnabled())
+    return;
+
   // This method should be called only when the resolved proxy was a data
   // saver proxy.
   DCHECK(request.url().is_valid());
   DCHECK(!request.url().SchemeIsCryptographic());
   DCHECK(request.url().SchemeIsHTTPOrHTTPS());
 
   if (request_headers->HasHeader(chrome_proxy_ect_header()))
     request_headers->RemoveHeader(chrome_proxy_ect_header());
 
   if (request.context()->network_quality_estimator()) {
@@ skipping 16 matching lines @@
                 "ECT enum value is not handled.");
   static_assert(net::EFFECTIVE_CONNECTION_TYPE_4G + 1 ==
                     net::EFFECTIVE_CONNECTION_TYPE_LAST,
                 "ECT enum value is not handled.");
 }
 
 void DataReductionProxyNetworkDelegate::RemoveChromeProxyECTHeader(
     net::HttpRequestHeaders* request_headers) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  if (!data_reduction_proxy::features::IsDataReductionProxyECTHeaderEnabled())
+    return;
+
   request_headers->RemoveHeader(chrome_proxy_ect_header());
 }
 
 }  // namespace data_reduction_proxy