'Basic' has an incorrect calt feature for gg

Summary:
========
Basic, One of the hosted fonts, has bogus rendering features depending on the 
processing option for the 'gg' sequence of characters.
https://bugzilla.mozilla.org/show_bug.cgi?id=1048324

In Details:
===========
Steps to reproduce:

Use a word with the character sequence "gg" (e.g. eggplant) in an html page and 
set 'font-family' to 'Basic' after including the webfont 'Basic':

http://www.google.com/fonts/specimen/Basic

Example:
-
http://jsbin.com/bojonefa/1

Actual results:

The character sequence "gg" gets rendered as "xg" where the colors of the "x" 
are inverted. This happens only if the webfont 'Basic' is used.
I experienced this issue in FF 30 and 31.

Other online Examples:
-
http://veliawortman.net/therapists/goetz.html

-
http://www.mansmarbles.com/#!Gold-Digger-Prank-/c14e7/CAF1CEA1-5502-468D-838F-8F
E348926AC1

This is a font bug. That font has a 'calt' (contextual alternates) feature that 
replaces 'g' with .notdef when followed by another 'g'.

You can see the same behavior in Chrome if you set

  -webkit-font-feature-settings: "calt" on;

Original issue reported on code.google.com by dcrossland@google.com on 5 Aug 2014 at 3:17

vg / googlefontdirectory

'Basic' has an incorrect calt feature for gg #323