HIDL Return withDefault const

Bug: N/A
Test: N/A
Change-Id: I34a1a7ea54efd7aaaa722ed0b1b0840664c4e166
diff --git a/base/include/hidl/Status.h b/base/include/hidl/Status.h
index 74901bb..a204af5 100644
--- a/base/include/hidl/Status.h
+++ b/base/include/hidl/Status.h
@@ -235,9 +235,7 @@
         return mVal;
     }
 
-    T withDefault(T t) {
-        return isOk() ? mVal : t;
-    }
+    T withDefault(T t) const { return isOk() ? mVal : t; }
 };
 
 template<typename T> class Return<sp<T>> : public details::return_status {
@@ -264,9 +262,7 @@
         return mVal;
     }
 
-    sp<T> withDefault(sp<T> t) {
-        return isOk() ? mVal : t;
-    }
+    sp<T> withDefault(sp<T> t) const { return isOk() ? mVal : t; }
 };