Document formatting preferences don't always apply to braille in browse mode

[dkager]

Steps to reproduce:

1. Select a braille table that can report italic text.
2. From Preferences --> Document formatting, uncheck Font attributes.
3. Read the following line (tested with Firefox 55).

This is italic text.

Expected behavior:

The italic text is not marked as italic.

Actual behavior:

Speech does indeed not mention the italic attribute, but braille still shows it.

Other information

Can't reproduce in Word, so it seems specific to browse mode.

First reported by @rimas-kudelis in #1885 (comment). The key take-away point is that this problem is quite annoying for users on the web, and if unresolved may lead to people "fixing" braille tables to exclude bold/italic/etc altogether.

[bramd]

@dkager For completeness and to be able to reproduce, which table would support such attributes?

[dkager]

The Dutch tables, and probably UEB.

[dkager]

This can be fixed with a simple patch of braille.py to consider formatConfig before sending text formatting flags to liblouis.

A further optimization is to not fetch IA2 text attributes and object attributes if all the formatConfig options that rely on them are disabled. This saves a few COM calls but the gains are probably minimal.