Refactor MetricProducer so that a big chunk of boiler plate code can be removed.

Test: statsd_test
Change-Id: I62489b94c6dfceb0b08ce4147c331a8a785eabb4
diff --git a/cmds/statsd/Android.mk b/cmds/statsd/Android.mk
index 3c2f2d5..1804e53 100644
--- a/cmds/statsd/Android.mk
+++ b/cmds/statsd/Android.mk
@@ -37,6 +37,7 @@
     src/matchers/matcher_util.cpp \
     src/matchers/SimpleLogMatchingTracker.cpp \
     src/metrics/CountAnomalyTracker.cpp \
+    src/metrics/MetricProducer.cpp \
     src/metrics/CountMetricProducer.cpp \
     src/metrics/DurationMetricProducer.cpp \
     src/metrics/MetricsManager.cpp \