Amortize data usage using TrafficStats on Android.

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
index 126bf0131e5a342ca2cac54f023df18ff9ca704f..183246868627b346fdd4a02237e2f88e3344f680 100644
--- a/components/data_usage/core/data_use_aggregator.cc
+++ b/components/data_usage/core/data_use_aggregator.cc
@@ -4,6 +4,9 @@
 
 #include "components/data_usage/core/data_use_aggregator.h"
 
+#include <sstream>
+#include <string>
+
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 #include "net/base/network_change_notifier.h"
@@ -11,8 +14,10 @@
 
 namespace data_usage {
 
-DataUseAggregator::DataUseAggregator()
-    : off_the_record_tx_bytes_since_last_flush_(0),
+DataUseAggregator::DataUseAggregator(
+    scoped_ptr<DataUseAmortizer> data_use_amortizer)
+    : data_use_amortizer_(data_use_amortizer.Pass()),
+      off_the_record_tx_bytes_since_last_flush_(0),
       off_the_record_rx_bytes_since_last_flush_(0),
       is_flush_pending_(false),
       weak_ptr_factory_(this) {}
@@ -82,7 +87,11 @@ base::WeakPtr<DataUseAggregator> DataUseAggregator::GetWeakPtr() {
 void DataUseAggregator::FlushBufferedDataUse() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  // TODO(sclittle): Amortize data use on supported platforms.
+  if (data_use_amortizer_) {
+    data_use_amortizer_->Amortize(&buffered_data_use_,
+                                  off_the_record_tx_bytes_since_last_flush_,
+                                  off_the_record_rx_bytes_since_last_flush_);
+  }
 
   FOR_EACH_OBSERVER(Observer, observer_list_, OnDataUse(buffered_data_use_));