ExtendStorageStub added, it is aimed for extending objects backing store when it runs out of space.

src/x64/interface-descriptors-x64.cc

Index: src/x64/interface-descriptors-x64.cc
diff --git a/src/x64/interface-descriptors-x64.cc b/src/x64/interface-descriptors-x64.cc
index 84fdca4fb9226d6b3ff43f2eaadf7358a5380f03..003125d27044e4584992265a3e063b67955ec989 100644
--- a/src/x64/interface-descriptors-x64.cc
+++ b/src/x64/interface-descriptors-x64.cc
@@ -27,6 +27,9 @@ const Register VectorLoadICDescriptor::VectorRegister() { return rbx; }
 const Register StoreDescriptor::ReceiverRegister() { return rdx; }
 const Register StoreDescriptor::NameRegister() { return rcx; }
 const Register StoreDescriptor::ValueRegister() { return rax; }
+const Register ExtendStorageDescriptor::MapRegister() {
+  return StoreDescriptor::NameRegister();
+}
 
 
 const Register ElementTransitionAndStoreDescriptor::MapRegister() {