Adding deps to protobuf rules.

Change-Id: Ib1f4f1e061a55885389a7b51c98317ee241a1bba
diff --git a/build_tests/BUILD b/build_tests/BUILD
index be6a201..72dc6da 100644
--- a/build_tests/BUILD
+++ b/build_tests/BUILD
@@ -74,6 +74,14 @@
 proto_cc_library(
   name = 'proto_build_test_library',
   src = 'proto.proto',
+  deps = [
+    ':proto_build_test_library_base',
+  ],
+)
+
+proto_cc_library(
+  name = 'proto_build_test_library_base',
+  src = 'proto_base.proto',
 )
 
 cc_test(