Take 2: Integrate StateTracker into statsd

Changes in this CL compared to previous StateTracker version:
- MetricsManager parses StatsdConfig for State information and updates
MetricProducers accordingly
- MetricProducer implements StateListener
- MetricProducer has a list of atom ids of its slice_by_states and any
state maps from these states. MetricProducers are responsible for
handling the conversion from original state value to mapped state value.
- More unit tests added and e2e CountMetric test added

Test: bit statsd_test:*
Bug: 136566566
Change-Id: I07ce468733a1affcadf2be0206e081fddbbce4c5
diff --git a/cmds/statsd/Android.bp b/cmds/statsd/Android.bp
index cb27325..8af925a 100644
--- a/cmds/statsd/Android.bp
+++ b/cmds/statsd/Android.bp
@@ -230,6 +230,7 @@
         "tests/e2e/Anomaly_duration_sum_e2e_test.cpp",
         "tests/e2e/Attribution_e2e_test.cpp",
         "tests/e2e/ConfigTtl_e2e_test.cpp",
+        "tests/e2e/CountMetric_e2e_test.cpp",
         "tests/e2e/DurationMetric_e2e_test.cpp",
         "tests/e2e/GaugeMetric_e2e_pull_test.cpp",
         "tests/e2e/GaugeMetric_e2e_push_test.cpp",