Move element deletion into element handlers

src/elements.h

Index: src/elements.h
diff --git a/src/elements.h b/src/elements.h
index 420e60fdc1e54709d7345fddae61797dd684b7d3..b552286f0804798b9e3b35099d92fe56eb00391d 100644
--- a/src/elements.h
+++ b/src/elements.h
@@ -43,6 +43,10 @@ class ElementsAccessor {
                                        Object* receiver,
                                        uint32_t index) = 0;
 
+  virtual MaybeObject* Delete(JSObject* obj,
+                              uint32_t index,
+                              JSReceiver::DeleteMode mode) = 0;
+
   // Returns a shared ElementsAccessor for the specified ElementsKind.
   static ElementsAccessor* ForKind(JSObject::ElementsKind elements_kind) {
     ASSERT(elements_kind < JSObject::kElementsKindCount);