Preserve constant function transition when adding the same function.

Preserve constant function transition when adding the same function.

This should help in cases like:
function Constructor() {
  this.foo = constFunction;
  this.bar = "baz";
}

for (...) {
  o = new Constructor();
  // Constant call IC will work.
  o.foo();
  // Inlined property load will see the same map.
  use(o.bar);
}

This change also fixes a latent bug in custom call IC-s for strings
exposed by string-charcodeat.js.

Committed: http://code.google.com/p/v8/source/detail?r=5254

[Vitaly Repeshko, 2010-08-12 13:29:08]

Adding antonm who co-authored this change.


-- Vitaly

[Mads Ager (chromium), 2010-08-12 13:41:57]

LGTM!