Split out proguard_basic_keeps.flags

For 'LOCAL_PROGUARD_ENABLED := nosystem' we still include
proguard_basic_keeps.flags.

Change-Id: I43ee7e98d2aaeb84879441f90ab6839c0e8f4e65
diff --git a/core/java.mk b/core/java.mk
index ebfff18..f43bf3b 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -401,6 +401,8 @@
 ifneq ($(strip $(LOCAL_INSTRUMENTATION_FOR)$(filter tests,$(LOCAL_MODULE_TAGS))$(filter android.test.runner,$(LOCAL_JAVA_LIBRARIES))),)
 proguard_flags := $(proguard_flags) -include $(BUILD_SYSTEM)/proguard_tests.flags
 endif # test package
+else  # LOCAL_PROGUARD_ENABLED is nosystem
+proguard_flags += -include $(BUILD_SYSTEM)/proguard_basic_keeps.flags
 endif # LOCAL_PROGUARD_ENABLED is not nosystem
 
 ifneq ($(LOCAL_PROGUARD_ENABLED),)