Gauge metric producer.

Test: manual tests passed for pushed device temperature.
Change-Id: I7592a4c04666606b745cdb41db8f9d8a96a966da
diff --git a/cmds/statsd/Android.mk b/cmds/statsd/Android.mk
index c5805fbb..86f353b 100644
--- a/cmds/statsd/Android.mk
+++ b/cmds/statsd/Android.mk
@@ -46,6 +46,7 @@
     src/metrics/duration_helper/OringDurationTracker.cpp \
     src/metrics/duration_helper/MaxDurationTracker.cpp \
     src/metrics/ValueMetricProducer.cpp \
+    src/metrics/GaugeMetricProducer.cpp \
     src/metrics/MetricsManager.cpp \
     src/metrics/metrics_manager_util.cpp \
     src/packages/UidMap.cpp \