forceURI: function(uri, fallback, ctx) {
    if (this.mustForce(uri)) {
      try {

        uri.scheme = "https";

        this.log("Forced URI " + uri.spec);
        return true;

      } catch(e) {

        if (ctx && ctx instanceof CI.nsIDOMHTMLImageElement || ctx instanceof CI.nsIDOMHTMLInputElement ||
            ctx instanceof CI.nsIObjectLoadingContent) {
          uri = uri.clone();
          uri.scheme = "https";

          var type, attr;
          if (ctx instanceof CI.nsIObjectLoadingContent) {
            type = "Object";
            attr = "data";
          } else {
            type = "Image";
            attr = "src";
          }
          Thread.asap(function() { ctx.setAttribute(attr, uri.spec); });

          var msg = type + " HTTP->HTTPS redirection to " + uri.spec;
          this.log(msg);
          throw msg;
        }

        if (fallback && fallback()) {
           this.log("Channel redirection fallback on " + uri.spec);
           return true;
        }

        this.log("Error trying to force https on " + uri.spec + ": " + e);
      }
    }
    return false;
  },