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

src/hydrogen.h

Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index 6b031708c767cbcdbd596e58c9959a513a8b40ac..a75406bb0c906010e2c60bc83a9032710bfee086 100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -1804,8 +1804,9 @@ class HGraphBuilder {
                                      ElementsKind kind,
                                      HValue* capacity);
 
-  HValue* BuildAllocateElementsAndInitializeElementsHeader(ElementsKind kind,
-                                                           HValue* capacity);
+  // Build allocation and header initialization code for respective successor
+  // of FixedArrayBase.
+  HValue* BuildAllocateAndInitializeArray(ElementsKind kind, HValue* capacity);
 
   // |array| must have been allocated with enough room for
   // 1) the JSArray and 2) an AllocationMemento if mode requires it.
@@ -1837,6 +1838,9 @@ class HGraphBuilder {
                                  HValue* from,
                                  HValue* to);
 
+  void BuildCopyProperties(HValue* from_properties, HValue* to_properties,
+                           HValue* length, HValue* capacity);
+
   void BuildCopyElements(HValue* from_elements,
                          ElementsKind from_elements_kind,
                          HValue* to_elements,