Simplify the LookupIterator

src/lookup-inl.h

 // Copyright 2014 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_LOOKUP_INL_H_
 #define V8_LOOKUP_INL_H_
 
 #include "src/lookup.h"
 
 namespace v8 {
@@ skipping 29 matching lines @@
       if (map->IsJSProxyMap()) return JSPROXY;
       if (map->is_access_check_needed()) return ACCESS_CHECK;
     // Fall through.
     case ACCESS_CHECK:
       if (check_interceptor() && map->has_named_interceptor()) {
         return INTERCEPTOR;
       }
     // Fall through.
     case INTERCEPTOR:
       if (map->is_dictionary_map()) {
-        if (holder == NULL) return UNKNOWN;
         NameDictionary* dict = JSObject::cast(holder)->property_dictionary();
         number_ = dict->FindEntry(name_);
         if (number_ == NameDictionary::kNotFound) return NOT_FOUND;
         property_details_ = dict->DetailsAt(number_);
         if (holder->IsGlobalObject()) {
           if (property_details_.IsDeleted()) return NOT_FOUND;
           PropertyCell* cell = PropertyCell::cast(dict->ValueAt(number_));
           if (cell->value()->IsTheHole()) return NOT_FOUND;
         }
       } else {
         DescriptorArray* descriptors = map->instance_descriptors();
         number_ = descriptors->SearchWithCache(*name_, map);
         if (number_ == DescriptorArray::kNotFound) return NOT_FOUND;
         property_details_ = descriptors->GetDetails(number_);
       }
       has_property_ = true;
       switch (property_details_.type()) {
         case v8::internal::CONSTANT:
         case v8::internal::FIELD:
         case v8::internal::NORMAL:
           return DATA;
         case v8::internal::CALLBACKS:
           return ACCESSOR;
       }
     case ACCESSOR:
     case DATA:
-    case UNKNOWN:
       return NOT_FOUND;
     case JSPROXY:
     case TRANSITION:
       UNREACHABLE();
   }
   UNREACHABLE();
   return state_;
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_LOOKUP_INL_H_