Robert's approach is a solution ...
Ie, Paste the link provided by Google into your browser and then add all the files referenced by your manifest.
In my case, I referred to
<link href='http://fonts.googleapis.com/css?family=Patua+One' rel='stylesheet' type='text/css'>
which consists only of the following style definition
@font-face { font-family: 'Patua One'; font-style: normal; font-weight: 400; src: local('Patua One'), local('PatuaOne-Regular'), url('http://themes.googleusercontent.com/static/fonts/patuaone/v3/yAXhog6uK3bd3OwBILv_SD8E0i7KZn-EPnyo3HZu7kw.woff') format('woff'); }
So, to make the font work when caching (off-line or not), you need to add the URL specified in "src" to your manifest.
Dylsexia
source share