Stop displaying FontSizePicker dropdown when there are no fonts.

[Naerriel]

Description

Closes #11628.
The FontSizePicker currently displays a dropdown with fonts, even when there are no fonts.
This change stops displaying the dropdown in this case.

How has this been tested?

In packages/components/src/font-size-picker/index.js I overwrote fontSizes to [] and the dropdown would not display anymore.
Ran npm run test and see that all tests passes.

Screenshots

Types of changes

Bug fix.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[chrisvanpatten]

@Naerriel What was the PHP you used to set the font sizes to empty?

[Naerriel]

@chrisvanpatten Excellent question. I haven't used the PHP, I set it in JS.
I forgot about that part of the issue. I don't know how to do that and whether it is even possible.

Possible solutions:

1. Modify the default WordPress behaviour to allow disabling editor font sizes (has probably no use case).
2. Close the Pull Request.

I'm not sure if I have got the call to action reached in #11628 correctly as well.
I could delete the Dropdown alongside the reset button, if there is one editor font size and the custom font sizes are disabled, which was the expected behaviour posed by the original poster.

What do you think?

[chrisvanpatten]

@Naerriel we do have a PHP function for pre-defining the dropdown sizes, add_theme_support( 'editor-font-sizes', (array) $sizes ); but from what I don't know if it's possible to set an empty array. If that is possible, and works in combination with this PR, it seems like a great fix. If it isn't possible it might be worth a core patch to allow that behavior so this can land.

[Naerriel]

@chrisvanpatten Yes, when you asked your question, I tried to do it in several ways but none worked.

I can patch this behaviour in the core, but I don't think people will use it. If you think that this should be done, I can get my hands on that 😄

[jorgefilipecosta]

Thank you for your contribution @Naerriel and thank you for reviewing @chrisvanpatten 👍
It should be possible to use add_theme_support( 'editor-font-sizes', array() );. But there is a bug that is affecting this change. I will open a follow-up PR to address this problem.
The change in this PR makes total sense and fixes a bug where the dropdown renders incorrectly so independently of the other bug so I'm going to merge it and then we can continue the iteration.

[nervewax]

@jorgefilipecosta Are you able to link to your pull/issue relating to the fix preventing add_theme_support( 'editor-font-sizes' ) from acting the same way as add_theme_support( 'editor-color-palette' )?

This issue was closed, however the original problem still exists.

[aduth]

@nervewax It can be found at:

• Fix: Impossible to set empty array on editor-font-sizes. #13824
• https://core.trac.wordpress.org/ticket/46290