Fast path for searching through simple transitions

Review URL: https://chromiumcodereview.appspot.com/11189089

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12778 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/transitions-inl.h

@@ -191,6 +191,11 @@ PropertyDetails TransitionArray::GetTargetDetails(int transition_number) {
 
 
 int TransitionArray::Search(String* name) {
+  if (IsSimpleTransition()) {
+    String* key = GetKey(kSimpleTransitionIndex);
+    if (key->Equals(name)) return kSimpleTransitionIndex;
+    return kNotFound;
+  }
   return internal::Search<ALL_ENTRIES>(this, name);
 }