Create a DataUseRecorder instance for each page load in Chrome.

components/data_use_measurement/core/data_use_ascriber.cc

 // Copyright 2016 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_use_measurement/core/data_use_ascriber.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
 #include "components/data_use_measurement/core/data_use_network_delegate.h"
 #include "components/data_use_measurement/core/data_use_recorder.h"
 #include "components/data_use_measurement/core/url_request_classifier.h"
 
 namespace data_use_measurement {
 
 std::unique_ptr<net::NetworkDelegate> DataUseAscriber::CreateNetworkDelegate(
     std::unique_ptr<net::NetworkDelegate> wrapped_network_delegate,
     const metrics::UpdateUsagePrefCallbackType& metrics_data_use_forwarder) {
   return base::MakeUnique<data_use_measurement::DataUseNetworkDelegate>(
       std::move(wrapped_network_delegate), this, CreateURLRequestClassifier(),
       metrics_data_use_forwarder);
 }
 
 void DataUseAscriber::OnBeforeUrlRequest(net::URLRequest* request) {
-  DataUseRecorder* recorder = GetDataUseRecorder(request);
+  DataUseRecorder* recorder = GetDataUseRecorder(request, true);
   if (recorder)
     recorder->OnBeforeUrlRequest(request);
 }
 
-void DataUseAscriber::OnBeforeRedirect(net::URLRequest* request,
-                                       const GURL& new_location) {}
-
 void DataUseAscriber::OnNetworkBytesSent(net::URLRequest* request,
                                          int64_t bytes_sent) {
-  DataUseRecorder* recorder = GetDataUseRecorder(request);
+  DataUseRecorder* recorder = GetDataUseRecorder(request, false);
   if (recorder)
     recorder->OnNetworkBytesSent(request, bytes_sent);
 }
 
 void DataUseAscriber::OnNetworkBytesReceived(net::URLRequest* request,
                                              int64_t bytes_received) {
-  DataUseRecorder* recorder = GetDataUseRecorder(request);
+  DataUseRecorder* recorder = GetDataUseRecorder(request, false);
   if (recorder)
     recorder->OnNetworkBytesReceived(request, bytes_received);
 }
 
+void DataUseAscriber::OnUrlRequestCompleted(net::URLRequest* request,
+                                            bool started) {}
+
 void DataUseAscriber::OnUrlRequestDestroyed(net::URLRequest* request) {
-  DataUseRecorder* recorder = GetDataUseRecorder(request);
-  // TODO(kundaji): Enforce DCHECK(recorder).
+  DataUseRecorder* recorder = GetDataUseRecorder(request, true);
   if (recorder)
     recorder->OnUrlRequestDestroyed(request);
 }
 
 }  // namespace data_use_measurement