Add StatsdStats and guardrail.

+ StatsdStats is the global class that tracks the stats about statsd.

+ Added guardrail for classes that have a map which could potentially grow
  unboundedly with the number of logs.

TODO: add unit tests & CTS for StatsdStats, and guardrail
      add stats for pulled atoms.

Test: statsd_test

Change-Id: I0ea562de4dd3f6162f7923a9c193420b482c1d51
diff --git a/cmds/statsd/src/metrics/EventMetricProducer.cpp b/cmds/statsd/src/metrics/EventMetricProducer.cpp
index 567b4c7..95a18f7 100644
--- a/cmds/statsd/src/metrics/EventMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/EventMetricProducer.cpp
@@ -51,10 +51,11 @@
 const int FIELD_ID_TIMESTAMP_NANOS = 1;
 const int FIELD_ID_ATOMS = 2;
 
-EventMetricProducer::EventMetricProducer(const EventMetric& metric, const int conditionIndex,
+EventMetricProducer::EventMetricProducer(const ConfigKey& key, const EventMetric& metric,
+                                         const int conditionIndex,
                                          const sp<ConditionWizard>& wizard,
                                          const uint64_t startTimeNs)
-    : MetricProducer(startTimeNs, conditionIndex, wizard), mMetric(metric) {
+    : MetricProducer(key, startTimeNs, conditionIndex, wizard), mMetric(metric) {
     if (metric.links().size() > 0) {
         mConditionLinks.insert(mConditionLinks.begin(), metric.links().begin(),
                                metric.links().end());