Implement UMA log throttling for cellular connections

components/data_use_measurement/content/data_use_measurement.cc

Index: components/data_use_measurement/content/data_use_measurement.cc
diff --git a/components/data_use_measurement/content/data_use_measurement.cc b/components/data_use_measurement/content/data_use_measurement.cc
index 23f916c6ae054c38efb296be694b623aa91cd5ab..636264eeb3cd7d3190b0a1e7cf407144984e1b3b 100644
--- a/components/data_use_measurement/content/data_use_measurement.cc
+++ b/components/data_use_measurement/content/data_use_measurement.cc
@@ -88,14 +88,22 @@ void DataUseMeasurement::ReportDataUseUMA(
 
   DataUseUserData* attached_service_data = reinterpret_cast<DataUseUserData*>(
       request->GetUserData(DataUseUserData::kUserDataKey));
-
+  DataUseUserData::ServiceName service_name =
+      attached_service_data ? attached_service_data->service_name()
+                            : DataUseUserData::NOT_TAGGED;
   if (!is_user_traffic) {
-    DataUseUserData::ServiceName service_name =
-        attached_service_data ? attached_service_data->service_name()
-                              : DataUseUserData::NOT_TAGGED;
     ReportDataUsageServices(service_name, UPSTREAM, total_upload_bytes);
     ReportDataUsageServices(service_name, DOWNSTREAM, total_received_bytes);
   }
+
+  // Update data use prefs for cellular connections.
+  bool is_cellular = net::NetworkChangeNotifier::IsConnectionCellular(
+      net::NetworkChangeNotifier::GetConnectionType());

[Alexei Svitkine (slow), 2016/03/31 04:32:25]

This already gets queried inside the GetHistogramName() calls above. Can you
move this up above that code and make GetHistogramName() take the boolean as a
param so this is only done once?

[gayane -on leave until 09-2017, 2016/03/31 17:54:58]

Done.

+  if (is_cellular && !metrics_data_use_forwarder_.is_null()) {
+    metrics_data_use_forwarder_.Run(
+        attached_service_data->GetServiceNameAsString(service_name),
+        total_upload_bytes + total_received_bytes);
+  }
 }
 
 #if defined(OS_ANDROID)
@@ -146,4 +154,9 @@ void DataUseMeasurement::ReportDataUsageServices(
   }
 }
 
+void DataUseMeasurement::SetMetricsDataUseForwarder(
+    metrics::UpdateUsagePrefCallbackType metrics_data_use_forwarder) {
+  metrics_data_use_forwarder_ = metrics_data_use_forwarder;
+}
+
 }  // namespace data_use_measurement