Include Metric Unit Tests

Merge from Widevine repo of http://go/wvgerrit/23842

This CL updates the android make files and test scripts to include the
two new unit test suites in metrics/test.

Change-Id: Ie31bdc3ae3709ab116d2a340ee5b55c7c12d1d33

libwvdrmengine/cdm/test/Android.mk

@@ -71,5 +71,13 @@ test_name := timer_unittest
 test_src_dir := .
 include $(LOCAL_PATH)/unit-test.mk
 
+test_name := distribution_test
+test_src_dir := ../metrics/test
+include $(LOCAL_PATH)/unit-test.mk
+
+test_name := event_metric_test
+test_src_dir := ../metrics/test
+include $(LOCAL_PATH)/unit-test.mk
+
 test_name :=
 test_src_dir :=