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..46af75c33391aa9649c9c2197fe93a072033ecca 100644
--- a/src/x87/interface-descriptors-x87.cc
+++ b/src/x87/interface-descriptors-x87.cc
@@ -29,6 +29,9 @@ const Register StoreDescriptor::NameRegister() { return ecx; }
 const Register StoreDescriptor::ValueRegister() { return eax; }
 
 
+const Register ExtendStorageDescriptor::MapRegister() { return ebx; }
+
+
 const Register ElementTransitionAndStoreDescriptor::MapRegister() {
   return ebx;
 }