Implement handlified String::Flatten.

src/objects.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 8987 matching lines @@
   //
   // Use FlattenString from Handles.cc to flatten even in case an
   // allocation failure happens.
   inline MaybeObject* TryFlatten(PretenureFlag pretenure = NOT_TENURED);
 
   // Convenience function.  Has exactly the same behavior as
   // TryFlatten(), except in the case of failure returns the original
   // string.
   inline String* TryFlattenGetString(PretenureFlag pretenure = NOT_TENURED);
 
+  static inline Handle<String> Flatten(Handle<String> string,
+                                       PretenureFlag pretenure = NOT_TENURED);
+
+  static Handle<String> SlowFlatten(Handle<ConsString> cons,
+                                    PretenureFlag tenure);
+
+
   // Tries to return the content of a flat string as a structure holding either
   // a flat vector of char or of uc16.
   // If the string isn't flat, and therefore doesn't have flat content, the
   // returned structure will report so, and can't provide a vector of either
   // kind.
   FlatContent GetFlatContent();
 
   // Returns the parent of a sliced string or first part of a flat cons string.
   // Requires: StringShape(this).IsIndirect() && this->IsFlat()
   inline String* GetUnderlying();
@@ skipping 1986 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_