Windows and .url files and nsILocalFileWin

Hello,
so I'm working on http://bugzilla.mozilla.org/show_bug.cgi?id=69114

That requires code to get from a .url file to the URL it links to.

Currently, such code exists in both xpfe/components/bookmarks and 
widget/src/windows. (function ResolveShortcut)

That bug would require adding similar code to netwerk/protocol/file/src.

Now, I don't like copying this code into another file.
Darin suggested creating a new interface nsILocalFileWin for this purpose.

The function on that interface would look something like this:

    /**
     * Checks if the file is an internet shortcut (.url file) and
     * returns the url pointed to if so.
     * Returns NS_ERROR_NOT_AVAILABLE otherwise
     */
    string resolveShortcut();

(nsILocalFile would be QIable to nsILocalFileWin then, on windows 
platforms.)

string instead of nsIURI because this is xpcom (=> no necko), and 
because the current callers want a string.

So. this is my proposal. Any comments on this?

-biesi