Use the LookupIterator for SetElement and friends

src/api.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_API_H_
 #define V8_API_H_
 
 #include "src/v8.h"
 
 #include "include/v8-testing.h"
@@ skipping 77 matching lines @@
 
 
 void NeanderObject::set(int offset, v8::internal::Object* value) {
   DCHECK(value_->HasFastObjectElements());
   v8::internal::FixedArray::cast(value_->elements())->set(offset, value);
 }
 
 
 template <typename T> inline T ToCData(v8::internal::Object* obj) {
   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
+  if (obj == v8::internal::Smi::FromInt(0)) return nullptr;
   return reinterpret_cast<T>(
       reinterpret_cast<intptr_t>(
           v8::internal::Foreign::cast(obj)->foreign_address()));
 }
 
 
 template <typename T>
 inline v8::internal::Handle<v8::internal::Object> FromCData(
     v8::internal::Isolate* isolate, T obj) {
   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
+  if (obj == nullptr) return handle(v8::internal::Smi::FromInt(0), isolate);
   return isolate->factory()->NewForeign(
       reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
 }
 
 
 class ApiFunction {
  public:
   explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
   v8::internal::Address address() { return addr_; }
  private:
@@ skipping 596 matching lines @@
     stress_type_ = stress_type;
   }
 
  private:
   static v8::Testing::StressType stress_type_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_API_H_