Add additional const

Change-Id: Ibf60cd4cfbb445189efe2439899f2a7084f1ea63
diff --git a/compiler/driver/compiler_callbacks_impl.h b/compiler/driver/compiler_callbacks_impl.h
index ab57832..fd2cd4a 100644
--- a/compiler/driver/compiler_callbacks_impl.h
+++ b/compiler/driver/compiler_callbacks_impl.h
@@ -50,8 +50,8 @@
     }
 
   private:
-    VerificationResults* verification_results_;
-    DexFileToMethodInlinerMap* method_inliner_map_;
+    VerificationResults* const verification_results_;
+    DexFileToMethodInlinerMap* const method_inliner_map_;
 };
 
 }  // namespace art