metrics_collector: Fix build of tests

IMetricsCollectorService implementation moved from libmetricscollectorservice
to metrics_collector executable, which means it needs to be compiled into test
main as well.

Bug: None
Change-Id: I29b0a3ae6164d2256366d61c3a3639d22b943a69
diff --git a/metricsd/Android.mk b/metricsd/Android.mk
index 89e4e93..7381703 100644
--- a/metricsd/Android.mk
+++ b/metricsd/Android.mk
@@ -28,6 +28,7 @@
   collectors/cpu_usage_collector.cc \
   collectors/disk_usage_collector.cc \
   metrics_collector.cc \
+  metrics_collector_service_impl.cc \
   persistent_integer.cc
 
 metricsd_common := \
@@ -165,8 +166,7 @@
 LOCAL_REQUIRED_MODULES := metrics.json
 LOCAL_SHARED_LIBRARIES := $(metrics_collector_shared_libraries)
 LOCAL_SRC_FILES := $(metrics_collector_common) \
-  metrics_collector_main.cc \
-  metrics_collector_service_impl.cc
+  metrics_collector_main.cc
 LOCAL_STATIC_LIBRARIES := metricsd_binder_proxy \
   $(metrics_collector_static_libraries)
 include $(BUILD_EXECUTABLE)