On a scaled canvas, a cache is scaled twice if the cache made after added to layer

On a stage with scale {x: 2, y:2}:

If a cache made before added to the layer, it works as expected:
http://jsfiddle.net/kzhdev/EY3A6/12/

If a cache made after added to the layer, the cache is scaled twice.
http://jsfiddle.net/kzhdev/EY3A6/13/

It looks like when drawing a cache, it needs to take account layer scale.
