Wrap JSFunction bindings in a helper object

src/runtime/runtime-object.cc

Index: src/runtime/runtime-object.cc
diff --git a/src/runtime/runtime-object.cc b/src/runtime/runtime-object.cc
index 4782a3143056b155db1304af871a84e52cb1f78a..0c842852b8711f830ec72af9e7ef0f22f2af155e 100644
--- a/src/runtime/runtime-object.cc
+++ b/src/runtime/runtime-object.cc
@@ -1586,9 +1586,8 @@ RUNTIME_FUNCTION(Runtime_InstanceOf) {
   if (callable->IsJSFunction()) {
     Handle<JSFunction> function = Handle<JSFunction>::cast(callable);
     if (function->shared()->bound()) {
-      Handle<FixedArray> bindings(function->function_bindings(), isolate);
-      callable =
-          handle(bindings->get(JSFunction::kBoundFunctionIndex), isolate);
+      Handle<BindingsArray> bindings(function->function_bindings(), isolate);
+      callable = handle(bindings->bound_function(), isolate);
     }
   }
   DCHECK(callable->IsCallable());