Create component to expose network usage stats to consumers.

components/data_usage/core/data_use_aggregator.cc

Index: components/data_usage/core/data_use_aggregator.cc
diff --git a/components/data_usage/core/data_use_aggregator.cc b/components/data_usage/core/data_use_aggregator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..802d304002e8a29d8871c1d85e82e520dce7ab44
--- /dev/null
+++ b/components/data_usage/core/data_use_aggregator.cc
@@ -0,0 +1,55 @@
+// Copyright 2015 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_usage/core/data_use_aggregator.h"
+
+#include "net/base/network_change_notifier.h"
+#include "net/url_request/url_request.h"
+
+namespace data_usage {
+
+DataUseAggregator::DataUseAggregator() {}
+
+DataUseAggregator::~DataUseAggregator() {}
+
+void DataUseAggregator::AddObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observer_list_.AddObserver(observer);
+}
+
+void DataUseAggregator::RemoveObserver(Observer* observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  observer_list_.RemoveObserver(observer);
+}
+
+void DataUseAggregator::ReportDataUse(const net::URLRequest& request,
+                                      int32_t tab_id,
+                                      int64_t tx_bytes,
+                                      int64_t rx_bytes) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // TODO(sclittle): Once actual buffering/aggregation is being done, consider
+  // combining consecutive data use entries from the same request.
+  DataUse data_use(request.url(), request.request_time(),
+                   request.first_party_for_cookies(), tab_id,
+                   net::NetworkChangeNotifier::GetConnectionType(), tx_bytes,
+                   rx_bytes);
+
+  // TODO(sclittle): Buffer and amortize data use on supported platforms.
+  NotifyDataUse(std::vector<DataUse>(1, data_use));
+}
+
+void DataUseAggregator::ReportOffTheRecordDataUse(int64_t tx_bytes,
+                                                  int64_t rx_bytes) {
+  // TODO(sclittle): Once data usage amortization is implemented, keep track of
+  // the off-the-record bytes so that they can be taken out of the amortized
+  // data usage calculations if applicable.

[tbansal1, 2015/10/08 04:22:44]

DCHECK(thread_checker_.CalledOnValidThread());

[sclittle, 2015/10/08 19:44:13]

Done.

+}
+
+void DataUseAggregator::NotifyDataUse(
+    const std::vector<DataUse>& data_use_sequence) {
+  FOR_EACH_OBSERVER(Observer, observer_list_, OnDataUse(data_use_sequence));
+}
+
+}  // namespace data_usage