Amortize data usage using TrafficStats on Android.

components/data_usage/core/data_use_aggregator.h

Index: components/data_usage/core/data_use_aggregator.h
diff --git a/components/data_usage/core/data_use_aggregator.h b/components/data_usage/core/data_use_aggregator.h
index bd5bab9fb01ca3b22af4d34efb59b043533259cb..fd785545a2ae8e97cd49b3974f54497b55682974 100644
--- a/components/data_usage/core/data_use_aggregator.h
+++ b/components/data_usage/core/data_use_aggregator.h
@@ -10,10 +10,12 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "components/data_usage/core/data_use.h"
+#include "components/data_usage/core/data_use_amortizer.h"
 
 namespace net {
 class URLRequest;
@@ -28,11 +30,10 @@ class DataUseAggregator {
   class Observer {
    public:
     virtual ~Observer() {}
-    // TODO(sclittle): Consider performing some pre-aggregation on the data use.
     virtual void OnDataUse(const std::vector<DataUse>& data_use_sequence) = 0;
   };
 
-  DataUseAggregator();
+  explicit DataUseAggregator(scoped_ptr<DataUseAmortizer> data_use_amortizer);
   virtual ~DataUseAggregator();
 
   void AddObserver(Observer* observer);
@@ -57,6 +58,8 @@ class DataUseAggregator {
   void FlushBufferedDataUse();
 
   base::ThreadChecker thread_checker_;
+
+  scoped_ptr<DataUseAmortizer> data_use_amortizer_;
   base::ObserverList<Observer> observer_list_;
 
   // Buffer of unreported data use.