The internal class for DOM prototypes is set to "Object". It should be set to "InterfaceNamePrototype". For example assertEquals('[object DocumentPrototype]',Object.prototype.toString.call(Document.prototype)) http://dev.w3.org/2006/webapi/WebIDL/#interface-prototype-object "The class string of an interface prototype object is the concatenation of the interface’s identifier and the string “Prototype”." This is causing one of the FAIL lines in LayoutTests/fast/dom/DOMException/prototype-object.html
Moved to https://code.google.com/p/chromium/issues/detail?id=239915