Add dex cache codegen helper function.

Change-Id: I02b0d3538dbbee03fb8837761b00ae1220d6902e
diff --git a/src/dex_cache.h b/src/dex_cache.h
index d87d8de..f748e57 100644
--- a/src/dex_cache.h
+++ b/src/dex_cache.h
@@ -69,13 +69,6 @@
     return GetLength() / kMax;
   }
 
- private:
-  enum TupleIndex {
-    kCode   = 0,
-    kMethod = 1,
-    kMax    = 2,
-  };
-
   static size_t CodeIndex(uint32_t method_idx) {
     return method_idx * kMax + kCode;
   }
@@ -83,6 +76,13 @@
     return method_idx * kMax + kMethod;
   }
 
+ private:
+  enum TupleIndex {
+    kCode   = 0,
+    kMethod = 1,
+    kMax    = 2,
+  };
+
   // grant friend status to ImageWriter fixup code that needs to know internal layout
   friend class ImageWriter;