Remove additional call to WP_Theme_JSON_Gutenberg::__construct

[kt-12]

What?

Introduce WP_Theme_JSON_Data_Gutenberg::get_theme_json() to avoid the cyclic call to WP_Theme_JSON_Gutenberg::__construct.

Trac ticket: Trac 61112

Why?

Doing similar changes in core, we got a consistent ~2.5% improvement by reducing 8 calls to the constructor reference core pr.

How?

WP_Theme_JSON_Data_Gutenberg internally has a theme_json private attribute which is an instance of WP_Theme_JSON_Gutenberg. At the moment we try to form the raw JSON data from the WP_Theme_JSON_Gutenberg object and then again from the Object from the raw JSON data, which leads to regression. In this PR we use the existing WP_Theme_JSON_Gutenberg object available to WP_Theme_JSON_Data_Gutenberg instead of the cyclic way.

Testing Instructions

Testing Instructions for Keyboard

Screenshots or screencast

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Co-authored-by: kt-12 <thekt12@git.wordpress.org>
Co-authored-by: oandregal <oandregal@git.wordpress.org>
Co-authored-by: joemcgill <joemcgill@git.wordpress.org>

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[oandregal]

See related feedback in the original wordpress-develop PR WordPress/wordpress-develop#6271

[oandregal]

A bit below, there's another WP_Theme_JSON_Data_Gutenberg call but we cannot update it as we do on this one. That code is different than the core code and we need to consolidate both. That's a follow-up PR that shouldn't prevent this one from landing.

[oandregal]

Perhaps we can absorb $config['isGlobalStylesUserThemeJSON'] = true; as part of WP_Theme_JSON_Data_Gutenberg. We may want to still check that's true before returning to be extra-safe (line 553) but we wouldn't need a second transformation.

[kt-12]

@oandregal I observed it but presumed that GB and Core might be doing things differently here. I'll look at how to incorporate that in a different PR.

[joemcgill]

Looks like the $config['isGlobalStylesUserThemeJSON'] modification was made as part of 2012a36 (#58409).

@ajlende is there a reason why this would still be necessary if we use the WP_Theme_JSON_Gutenberg object already present in the WP_Theme_JSON_Data_Gutenberg object?

[joemcgill]

This looks good to me. I think looking at the isGlobalStylesUserThemeJSON question can be resolved in a follow-up PR.

[joemcgill]

Looks like the $config['isGlobalStylesUserThemeJSON'] modification was made as part of 2012a36 (#58409).

@ajlende is there a reason why this would still be necessary if we use the WP_Theme_JSON_Gutenberg object already present in the WP_Theme_JSON_Data_Gutenberg object?

[joemcgill]

@oandregal I don't have permissions to merge this PR but am planning to commit the related Core PR this week. Can you help us get this one shipped in a GB release as well?