BitmapImage::imageForDefaultFrame() doesn't check, whether frame can be decoded

Hotfix to solve crash in webkit 

Reproduction:
Note: Source image can be later unavailable-
In console:

var oc = document.createElement('canvas');
 
var octx = this.oc.getContext('2d');
 
 
var elmImg = document.createElement("img");
 
 
elmImg.addEventListener("load",function(){
   octx.drawImage(elmImg, 0, 0);
});
 
 
elmImg.src = "http://www.minorit.com/favicon.ico";
document.body.appendChild(elmImg);
=== crashed here ===