An empty collector skeleton for a read barrier-based collector.

Bug: 12687968

Change-Id: Ic2a3a7b9943ca64e7f60f4d6ed552a316ea4a6f3
diff --git a/runtime/Android.mk b/runtime/Android.mk
index 1ca8e07..1576905 100644
--- a/runtime/Android.mk
+++ b/runtime/Android.mk
@@ -52,6 +52,7 @@
 	gc/accounting/mod_union_table.cc \
 	gc/accounting/remembered_set.cc \
 	gc/accounting/space_bitmap.cc \
+	gc/collector/concurrent_copying.cc \
 	gc/collector/garbage_collector.cc \
 	gc/collector/immune_region.cc \
 	gc/collector/mark_sweep.cc \