Keyed stores to super with numeric keys.

src/elements.h

Index: src/elements.h
diff --git a/src/elements.h b/src/elements.h
index f4de4bb010d560a695a3db9aa6576e95f283fe74..abe77ef3b4f2b75f39a299ecbd17bd8c0dfb8fb0 100644
--- a/src/elements.h
+++ b/src/elements.h
@@ -82,21 +82,23 @@ class ElementsAccessor {
   }
 
   // Returns an element's accessors, or NULL if the element does not exist or
-  // is plain. This method doesn't iterate up the prototype chain.  The caller
+  // is plain. The returned object represents callbacks to be executed for
+  // element access, and can be one of:
+  //   - AccessorPair
+  //   - ExecutableAccessorPair
+  //   - DeclaredAccessorInfo.
+  // This method doesn't iterate up the prototype chain.  The caller
   // can optionally pass in the backing store to use for the check, which must
   // be compatible with the ElementsKind of the ElementsAccessor. If
   // backing_store is NULL, the holder->elements() is used as the backing store.
-  MUST_USE_RESULT virtual MaybeHandle<AccessorPair> GetAccessorPair(
-      Handle<Object> receiver,
-      Handle<JSObject> holder,
-      uint32_t key,
+  // todo(dslomov): Update comment
+  MUST_USE_RESULT virtual MaybeHandle<Object> GetStructure(
+      Handle<Object> receiver, Handle<JSObject> holder, uint32_t key,
       Handle<FixedArrayBase> backing_store) = 0;
 
-  MUST_USE_RESULT inline MaybeHandle<AccessorPair> GetAccessorPair(
-      Handle<Object> receiver,
-      Handle<JSObject> holder,
-      uint32_t key) {
-    return GetAccessorPair(receiver, holder, key, handle(holder->elements()));
+  MUST_USE_RESULT inline MaybeHandle<Object> GetStructure(
+      Handle<Object> receiver, Handle<JSObject> holder, uint32_t key) {
+    return GetStructure(receiver, holder, key, handle(holder->elements()));
   }
 
   // Modifies the length data property as specified for JSArrays and resizes the