Add more statistics on failure cases for value metrics

This adds to PulledAtomStats and creates a new stats atom AtomMetricStats.

Test: none
Bug: 123572169
Change-Id: Ifea682005210a6342a027643e162f8ce7785cb06
diff --git a/cmds/statsd/src/stats_log_util.h b/cmds/statsd/src/stats_log_util.h
index 61f31eb..dcea0e6 100644
--- a/cmds/statsd/src/stats_log_util.h
+++ b/cmds/statsd/src/stats_log_util.h
@@ -73,6 +73,10 @@
 void writePullerStatsToStream(const std::pair<int, StatsdStats::PulledAtomStats>& pair,
                               util::ProtoOutputStream* protoOutput);
 
+// Helper function to write AtomMetricStats to ProtoOutputStream
+void writeAtomMetricStatsToStream(const std::pair<int, StatsdStats::AtomMetricStats> &pair,
+                                  util::ProtoOutputStream *protoOutput);
+
 template<class T>
 bool parseProtoOutputStream(util::ProtoOutputStream& protoOutput, T* message) {
     std::string pbBytes;