Add an about:flag to support alternative data saver features

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 <algorithm>
 #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/strings/string_split.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_headers.h"
@@ skipping 137 matching lines @@
                         util::CalculateEffectiveOCL(request)
                   : request.GetTotalReceivedBytes();
 }
 
 // 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()));
+    std::string chrome_proxy_header_value;
+    DCHECK(
+        headers.GetHeader(chrome_proxy_header(), &chrome_proxy_header_value));
+    // Check that only 1 "exp" directive is sent.
+    DCHECK_GT(3u, base::SplitStringUsingSubstr(chrome_proxy_header_value,
+                                               "exp=", base::TRIM_WHITESPACE,
+                                               base::SPLIT_WANT_ALL)
+                      .size());
+    // Silence unused variable warning in release builds.
+    (void)chrome_proxy_header_value;
   } 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 180 matching lines @@
   // crbug.com/709621
   if (request->load_flags() & net::LOAD_MAIN_FRAME_DEPRECATED) {
     if (!page_id) {
       page_id = data_reduction_proxy_request_options_->GeneratePageId();
     }
     data->set_page_id(page_id.value());
   }
 
   data_reduction_proxy_request_options_->AddRequestHeader(headers, page_id);
 
-  if (lofi_decider)
-    lofi_decider->MaybeSetIgnorePreviewsBlacklistDirective(headers);
   VerifyHttpRequestHeaders(true, *headers);
 }
 
 void DataReductionProxyNetworkDelegate::OnBeforeRedirectInternal(
     net::URLRequest* request,
     const GURL& new_location) {
   // Since this is after a redirect response, reset |request|'s
   // DataReductionProxyData, but keep page ID and session.
   // TODO(ryansturm): Change ClearData logic to have persistent and
   // non-persistent (WRT redirects) data.
@@ skipping 307 matching lines @@
 }
 
 void DataReductionProxyNetworkDelegate::RemoveChromeProxyECTHeader(
     net::HttpRequestHeaders* request_headers) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   request_headers->RemoveHeader(chrome_proxy_ect_header());
 }
 
 }  // namespace data_reduction_proxy