Remove the LookupResult IsValid method because it is confusing....

src/api.cc

 // Copyright 2009 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 2189 matching lines @@
 
 Local<Value> v8::Object::GetRealNamedPropertyInPrototypeChain(
       Handle<String> key) {
   ON_BAILOUT("v8::Object::GetRealNamedPropertyInPrototypeChain()",
              return Local<Value>());
   ENTER_V8;
   i::Handle<i::JSObject> self_obj = Utils::OpenHandle(this);
   i::Handle<i::String> key_obj = Utils::OpenHandle(*key);
   i::LookupResult lookup;
   self_obj->LookupRealNamedPropertyInPrototypes(*key_obj, &lookup);
-  if (lookup.IsValid()) {
+  if (lookup.IsProperty()) {
     PropertyAttributes attributes;
     i::Handle<i::Object> result(self_obj->GetProperty(*self_obj,
                                                       &lookup,
                                                       *key_obj,
                                                       &attributes));
     return Utils::ToLocal(result);
   }
   return Local<Value>();  // No real property was found in prototype chain.
 }
 
 
 Local<Value> v8::Object::GetRealNamedProperty(Handle<String> key) {
   ON_BAILOUT("v8::Object::GetRealNamedProperty()", return Local<Value>());
   ENTER_V8;
   i::Handle<i::JSObject> self_obj = Utils::OpenHandle(this);
   i::Handle<i::String> key_obj = Utils::OpenHandle(*key);
   i::LookupResult lookup;
   self_obj->LookupRealNamedProperty(*key_obj, &lookup);
-  if (lookup.IsValid()) {
+  if (lookup.IsProperty()) {
     PropertyAttributes attributes;
     i::Handle<i::Object> result(self_obj->GetProperty(*self_obj,
                                                       &lookup,
                                                       *key_obj,
                                                       &attributes));
     return Utils::ToLocal(result);
   }
   return Local<Value>();  // No real property was found in prototype chain.
 }
 
@@ skipping 1698 matching lines @@
 
 
 char* HandleScopeImplementer::Iterate(ObjectVisitor* v, char* storage) {
   HandleScopeImplementer* thread_local =
       reinterpret_cast<HandleScopeImplementer*>(storage);
   thread_local->IterateThis(v);
   return storage + ArchiveSpacePerThread();
 }
 
 } }  // namespace v8::internal