Use the LookupIterator for SetElement and friends

src/elements.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ELEMENTS_H_
 #define V8_ELEMENTS_H_
 
 #include "src/elements-kind.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
@@ skipping 25 matching lines @@
       Handle<JSObject> holder,
       uint32_t key,
       Handle<FixedArrayBase> backing_store) = 0;
 
   inline bool HasElement(
       Handle<JSObject> holder,
       uint32_t key) {
     return HasElement(holder, key, handle(holder->elements()));
   }
 
+  inline Handle<Object> Set(Handle<JSObject> holder, uint32_t key,
+                            Handle<Object> value) {
+    return Set(holder, key, handle(holder->elements()), value);
+  }
+
   // Returns the element with the specified key or undefined if there is no such
   // element. 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.
   virtual Handle<Object> Get(Handle<JSObject> holder, uint32_t key,
                              Handle<FixedArrayBase> backing_store) = 0;
 
   inline Handle<Object> Get(Handle<JSObject> holder, uint32_t key) {
     return Get(holder, key, handle(holder->elements()));
@@ skipping 124 matching lines @@
   // it is passed. In the NumberDictionary ElementsAccessor, GetKeyForIndex maps
   // the index to a key using the KeyAt method on the NumberDictionary.
   virtual uint32_t GetKeyForIndex(FixedArrayBase* backing_store,
                                   uint32_t index) = 0;
   virtual uint32_t GetIndexForKey(FixedArrayBase* backing_store,
                                   uint32_t key) = 0;
   virtual PropertyDetails GetDetails(FixedArrayBase* backing_store,
                                      uint32_t index) = 0;
   virtual bool HasIndex(FixedArrayBase* backing_store, uint32_t key) = 0;
 
+  virtual Handle<Object> Set(Handle<JSObject> holder, uint32_t key,
+                             Handle<FixedArrayBase> backing_store,
+                             Handle<Object> value) = 0;
+
  private:
   static ElementsAccessor** elements_accessors_;
   const char* name_;
 
   DISALLOW_COPY_AND_ASSIGN(ElementsAccessor);
 };
 
 void CheckArrayAbuse(Handle<JSObject> obj, const char* op, uint32_t key,
                      bool allow_appending = false);
 
 MUST_USE_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
     Handle<JSArray> array,
     Arguments* args);
 
 } }  // namespace v8::internal
 
 #endif  // V8_ELEMENTS_H_