[runtime] Better encapsulation of dictionary objects handling in lookup iterator.

src/lookup.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_H_
 #define V8_LOOKUP_H_
 
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects.h"
@@ skipping 172 matching lines @@
       }
     }
     return Handle<JSObject>::cast(receiver_);
   }
 
   bool is_dictionary_holder() const { return !holder_->HasFastProperties(); }
   Handle<Map> transition_map() const {
     DCHECK_EQ(TRANSITION, state_);
     return Handle<Map>::cast(transition_);
   }
+  Handle<PropertyCell> transition_cell() const {
+    DCHECK_EQ(TRANSITION, state_);
+    return Handle<PropertyCell>::cast(transition_);
+  }
   template <class T>
   Handle<T> GetHolder() const {
     DCHECK(IsFound());
     return Handle<T>::cast(holder_);
   }
 
   bool HolderIsReceiverOrHiddenPrototype() const;
 
   bool check_prototype_chain() const {
     return (configuration_ & kPrototypeChain) != 0;
@@ skipping 159 matching lines @@
   const Handle<JSReceiver> initial_holder_;
   const uint32_t index_;
   uint32_t number_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_LOOKUP_H_