Implement handlified String::Flatten.

src/objects-inl.h

 // Copyright 2012 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 3013 matching lines @@
 
 bool String::Equals(String* other) {
   if (other == this) return true;
   if (this->IsInternalizedString() && other->IsInternalizedString()) {
     return false;
   }
   return SlowEquals(other);
 }
 
 
+Handle<String> String::Flatten(Handle<String> string, PretenureFlag pretenure) {
+  if (!string->IsConsString()) return string;
+  Handle<ConsString> cons = Handle<ConsString>::cast(string);
+  if (cons->IsFlat()) return handle(cons->first());
+  return SlowFlatten(cons, pretenure);
+}
+
+
 MaybeObject* String::TryFlatten(PretenureFlag pretenure) {
   if (!StringShape(this).IsCons()) return this;
   ConsString* cons = ConsString::cast(this);
   if (cons->IsFlat()) return cons->first();
   return SlowTryFlatten(pretenure);
 }
 
 
 String* String::TryFlattenGetString(PretenureFlag pretenure) {
   MaybeObject* flat = TryFlatten(pretenure);
@@ skipping 3880 matching lines @@
 #undef READ_UINT32_FIELD
 #undef WRITE_UINT32_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_