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

src/x87/interface-descriptors-x87.cc

Index: src/x87/interface-descriptors-x87.cc
diff --git a/src/x87/interface-descriptors-x87.cc b/src/x87/interface-descriptors-x87.cc
index 8dfad3633cb6493844d847d404d761424718189a..bfb7b6eb3f9be4b5b26f4644d5dd58d24d3f778f 100644
--- a/src/x87/interface-descriptors-x87.cc
+++ b/src/x87/interface-descriptors-x87.cc
@@ -27,6 +27,9 @@ const Register VectorLoadICDescriptor::VectorRegister() { return ebx; }
 const Register StoreDescriptor::ReceiverRegister() { return edx; }
 const Register StoreDescriptor::NameRegister() { return ecx; }
 const Register StoreDescriptor::ValueRegister() { return eax; }
+const Register ExtendStorageDescriptor::MapRegister() {
+  return StoreDescriptor::NameRegister();
+}
 
 
 const Register ElementTransitionAndStoreDescriptor::MapRegister() {