Always report the metric id even if the metric has no data to upload.

This is to normalize the metric when applying cross-device aggregation.

Test: statsd test
BUG: b/118203108

Change-Id: I644a6a4163e2d2ad8f70e0c4e002dd4f542248af
diff --git a/cmds/statsd/src/metrics/EventMetricProducer.cpp b/cmds/statsd/src/metrics/EventMetricProducer.cpp
index a18e406..31a4361 100644
--- a/cmds/statsd/src/metrics/EventMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/EventMetricProducer.cpp
@@ -44,6 +44,7 @@
 // for StatsLogReport
 const int FIELD_ID_ID = 1;
 const int FIELD_ID_EVENT_METRICS = 4;
+const int FIELD_ID_IS_ACTIVE = 13;
 // for EventMetricDataWrapper
 const int FIELD_ID_DATA = 1;
 // for EventMetricData
@@ -108,10 +109,11 @@
                                              const bool erase_data,
                                              std::set<string> *str_set,
                                              ProtoOutputStream* protoOutput) {
+    protoOutput->write(FIELD_TYPE_INT64 | FIELD_ID_ID, (long long)mMetricId);
+    protoOutput->write(FIELD_TYPE_INT64 | FIELD_ID_IS_ACTIVE, isActiveLocked());
     if (mProto->size() <= 0) {
         return;
     }
-    protoOutput->write(FIELD_TYPE_INT64 | FIELD_ID_ID, (long long)mMetricId);
 
     size_t bufferSize = mProto->size();
     VLOG("metric %lld dump report now... proto size: %zu ",