Implement UMA log throttling for cellular connections

components/data_use_measurement/content/data_use_measurement.h

Index: components/data_use_measurement/content/data_use_measurement.h
diff --git a/components/data_use_measurement/content/data_use_measurement.h b/components/data_use_measurement/content/data_use_measurement.h
index a5b8f7136359a70c26fe085c11fb0471549bb004..36bcb5a2ba055a0e824233580fde453d9360ecee 100644
--- a/components/data_use_measurement/content/data_use_measurement.h
+++ b/components/data_use_measurement/content/data_use_measurement.h
@@ -9,10 +9,12 @@
 
 #include <string>
 
+#include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
 #include "components/data_use_measurement/core/data_use_user_data.h"
+#include "components/metrics/data_use_tracker.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/application_status_listener.h"
@@ -45,6 +47,10 @@ class DataUseMeasurement {
       base::android::ApplicationState application_state);
 #endif
 
+  // Sets callback for updating data use prefs.
+  void SetMetricsDataUseForwarder(
+      metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder);
+
  private:
   // Specifies that data is received or sent, respectively.
   enum TrafficDirection { DOWNSTREAM, UPSTREAM };
@@ -81,6 +87,9 @@ class DataUseMeasurement {
       TrafficDirection dir,
       int64_t message_size) const;
 
+  // Callback for updating data use prefs.
+  metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder_;
+
 #if defined(OS_ANDROID)
   // Application listener store the last known state of the application in this
   // field.