Implement a logic to rate limitted flush statsd with by checking the
size of each MetricsProducer's. The implementation of byteSize() method
is still TBD as it depends on migration to ProtoOutputStream.

Test: statsd, statsd_test
Change-Id: I966606044d7cb814dabe94192bacecad91f28177
diff --git a/cmds/statsd/src/metrics/DurationMetricProducer.cpp b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
index 38e55fd..a590bc8 100644
--- a/cmds/statsd/src/metrics/DurationMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/DurationMetricProducer.cpp
@@ -349,6 +349,13 @@
     }
 }
 
+size_t DurationMetricProducer::byteSize() {
+// TODO: return actual proto size when ProtoOutputStream is ready for use for
+// DurationMetricsProducer.
+//    return mProto->size();
+  return 0;
+}
+
 }  // namespace statsd
 }  // namespace os
 }  // namespace android