Called when the required favicon’s information is available.
It’s up to the invoking method to state if the callback is always invoked,
or called on success only. Check the method documentation to ensure that.
The caller will receive the most information we can gather on the icon,
but it’s not guaranteed that all of them will be set. For some method
we could not know the favicon’s data (it could just be too expensive to
get it, or the method does not require we actually have any data).
It’s up to the caller to check aDataLen > 0 before using any data-related
information like mime-type or data itself.
@note If you want to open a network channel to access the favicon, it’s
recommended that you call the getFaviconLinkForIcon method to convert
the “favicon URI” into a “favicon link URI”.
| aFaviconURI | Receives the "favicon URI" (not the "favicon link URI") associated to the requested page. This can be null if there is no associated favicon URI, or the callback is notifying a failure. |
| aDataLen | Size of the icon data in bytes. Notice that a value of 0 does not necessarily mean that we don't have an icon. |
| aData | Icon data, or an empty array if aDataLen is 0. |
| aMimeType | Mime type of the icon, or an empty string if aDataLen is 0. |