Refactor prototype setting code and expose SetPrototype to public V8 API.

src/handles.h

 // Copyright 2006-2008 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 222 matching lines @@
 Handle<Object> GetProperty(Handle<Object> obj,
                            Handle<Object> key);
 
 Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
                                           Handle<JSObject> holder,
                                           Handle<String> name,
                                           PropertyAttributes* attributes);
 
 Handle<Object> GetPrototype(Handle<Object> obj);
 
+Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value);
+
 // Return the object's hidden properties object. If the object has no hidden
 // properties and create_if_needed is true, then a new hidden property object
 // will be allocated. Otherwise the Heap::undefined_value is returned.
 Handle<Object> GetHiddenProperties(Handle<JSObject> obj, bool create_if_needed);
 
 Handle<Object> DeleteElement(Handle<JSObject> obj, uint32_t index);
 Handle<Object> DeleteProperty(Handle<JSObject> obj, Handle<String> prop);
 
 Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index);
 
@@ skipping 112 matching lines @@
  private:
   bool has_been_transformed_;  // Tells whether the object has been transformed.
   int unused_property_fields_;  // Captures the unused number of field.
   Handle<JSObject> object_;    // The object being optimized.
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_H_