Directly store the transition target on LookupResult in TransitionResult.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5537 matching lines @@
   if (lookup_.IsFound()) {
     if (IsLoad()) return true;
     return !lookup_.IsReadOnly() && lookup_.IsCacheable();
   }
   if (!LookupInPrototypes()) return false;
   if (IsLoad()) return true;
 
   if (lookup_.IsPropertyCallbacks()) return true;
   Handle<Map> map = this->map();
   map->LookupTransition(NULL, *name_, &lookup_);
-  if (lookup_.IsTransitionToField(*map) && map->unused_property_fields() > 0) {
-    transition_ = handle(lookup_.GetTransitionMapFromMap(*map));
+  if (lookup_.IsTransitionToField() && map->unused_property_fields() > 0) {
     return true;
   }
   return false;
 }
 
 
 bool HOptimizedGraphBuilder::PropertyAccessInfo::CanAccessAsMonomorphic(
     SmallMapList* types) {
   ASSERT(type_->Is(ToType(types->first())));
   if (!CanAccessMonomorphic()) return false;
@@ skipping 5721 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal