metricsd: Add tests to the default debug build.

This will allow the tests to be run by the continuous builder.

Bug: 26571398
Change-Id: I7eae2761603e83e3d1f003cb3b06582abc4ed24f
Test: Build an eng build. The tests are installed.
diff --git a/metricsd/Android.mk b/metricsd/Android.mk
index ed3fcbb..250c657 100644
--- a/metricsd/Android.mk
+++ b/metricsd/Android.mk
@@ -202,6 +202,9 @@
 LOCAL_SHARED_LIBRARIES := $(metricsd_shared_libraries)
 LOCAL_SRC_FILES := $(metricsd_tests_sources) $(metricsd_common)
 LOCAL_STATIC_LIBRARIES := libBionicGtestMain libgmock metricsd_protos metricsd_binder_proxy
+ifdef BRILLO
+LOCAL_MODULE_TAGS := debug
+endif
 include $(BUILD_NATIVE_TEST)
 
 # Unit tests for metrics_collector.
@@ -217,6 +220,9 @@
   $(metrics_collector_common)
 LOCAL_STATIC_LIBRARIES := libBionicGtestMain libgmock metricsd_binder_proxy \
   $(metrics_collector_static_libraries)
+ifdef BRILLO
+LOCAL_MODULE_TAGS := debug
+endif
 include $(BUILD_NATIVE_TEST)
 
 # Weave schema files