Replace the bool kDoReadBarrier template parameter with an enum.

Fix one kDoReadBarrier/kIsVolatile mixup in an Object::GetFieldObject
call.

Bug: 12687968

Change-Id: I896b1137b21a20c0504abd2bf3fe6f83805f3300
diff --git a/runtime/globals.h b/runtime/globals.h
index e3c54b8..eb52a46 100644
--- a/runtime/globals.h
+++ b/runtime/globals.h
@@ -20,6 +20,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include "read_barrier_c.h"
+#include "read_barrier_option.h"
 
 namespace art {