ART: More header cleanup - jni_internal.h

Move jni_macros.h to the clients (users of RegisterNativeMethods).

Test: mmma art
Change-Id: I052ac9f703ec69f0a2df1efcaf9f4a450eb7be1c
diff --git a/runtime/native/java_lang_StringFactory.cc b/runtime/native/java_lang_StringFactory.cc
index ec3c7c2..c1292ef 100644
--- a/runtime/native/java_lang_StringFactory.cc
+++ b/runtime/native/java_lang_StringFactory.cc
@@ -16,6 +16,8 @@
 
 #include "java_lang_StringFactory.h"
 
+#include "nativehelper/jni_macros.h"
+
 #include "common_throws.h"
 #include "jni_internal.h"
 #include "mirror/object-inl.h"