Create a DataUseRecorder instance for each page load in Chrome.

components/data_use_measurement/core/data_use_recorder.cc

Index: components/data_use_measurement/core/data_use_recorder.cc
diff --git a/components/data_use_measurement/core/data_use_recorder.cc b/components/data_use_measurement/core/data_use_recorder.cc
index ce45d1b7101eef0b2d2bfb5f25e62df23c30186e..8a25e7222c256a7b5d3a3b39b5d25c3286bd2dad 100644
--- a/components/data_use_measurement/core/data_use_recorder.cc
+++ b/components/data_use_measurement/core/data_use_recorder.cc
@@ -8,7 +8,7 @@
 
 namespace data_use_measurement {
 
-DataUseRecorder::DataUseRecorder() {}
+DataUseRecorder::DataUseRecorder() : main_url_request_(nullptr) {}
 
 DataUseRecorder::~DataUseRecorder() {}
 
@@ -16,7 +16,7 @@ bool DataUseRecorder::IsDataUseComplete() {
   return pending_url_requests_.empty() && pending_data_sources_.empty();
 }
 
-void DataUseRecorder::OnBeforeUrlRequest(net::URLRequest* request) {
+void DataUseRecorder::AddPendingURLRequest(net::URLRequest* request) {
   pending_url_requests_.insert(request);
 }
 
@@ -24,6 +24,12 @@ void DataUseRecorder::OnUrlRequestDestroyed(net::URLRequest* request) {
   pending_url_requests_.erase(request);
 }
 
+void DataUseRecorder::RemoveAllPendingURLRequests() {
+  pending_url_requests_.clear();
+}
+
+void DataUseRecorder::OnBeforeUrlRequest(net::URLRequest* request) {}
+
 void DataUseRecorder::OnNetworkBytesReceived(net::URLRequest* request,
                                              int64_t bytes_received) {
   data_use_.total_bytes_received_ += bytes_received;
@@ -46,8 +52,12 @@ void DataUseRecorder::RemovePendingDataSource(void* source) {
   pending_data_sources_.erase(source);
 }
 
-bool DataUseRecorder::HasPendingURLRequest(const net::URLRequest* request) {
+bool DataUseRecorder::HasPendingURLRequest(net::URLRequest* request) {
   return pending_url_requests_.find(request) != pending_url_requests_.end();
 }
 
+void DataUseRecorder::MergeFrom(DataUseRecorder* other) {
+  data_use_.MergeFrom(other->data_use());
+}
+
 }  // namespace data_use_measurement