Use MigrateToMap instead of set_map to update the map of a JSObject.

This is necessary to guarantee correct representation usage.
Some unhandlified code still needs to be handlified before we can push this
through fully.

BUG=
R=ishell@chromium.org

Review URL: https://codereview.chromium.org/194783002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19844 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.h

@@ -2874,15 +2874,6 @@ class JSObject: public JSReceiver {
                               ValueType value_type,
                               TransitionFlag flag);
 
-  // Add a property to a fast-case object using a map transition to
-  // new_map.
-  static void AddFastPropertyUsingMap(Handle<JSObject> object,
-                                      Handle<Map> new_map,
-                                      Handle<Name> name,
-                                      Handle<Object> value,
-                                      int field_index,
-                                      Representation representation);
-
   // Add a property to a slow-case object.
   static void AddSlowProperty(Handle<JSObject> object,
                               Handle<Name> name,