Ensures that intentional backslashes (e.g. "\o/") can be used in:
* Site title
* Site description
* Nav menu name
* Custom Menu widget title
* Tag Cloud widget title
* Text widget body if can't `unfiltered_html`
The latter three are also fixed on the widgets admin page.
Fixes#35898.
Built from https://develop.svn.wordpress.org/trunk@36622
git-svn-id: http://core.svn.wordpress.org/trunk@36589 1a063a9b-81f0-0310-95a4-ce76da25c4cd
* Introduce `customize_post_value_set_{$setting_id}` and `customize_post_value_set` actions which are done when `WP_Customize_Manager::set_post_value()` is called.
* Clear the `preview_applied` flag for aggregated multidimensional settings when a post value is set. This ensures the new value is used instead of a previously-cached previewed value.
* Move `$is_preview` property from subclasses to `WP_Customize_Setting` parent class.
* Deferred preview: Ensure that when `preview()` short-circuits due to not being applicable that it will be called again later when the post value is set.
* Populate post value for updated-widget with the (unsanitized) JS-value in `WP_Customize_Widgets::call_widget_update()` so that value will be properly sanitized when accessed in `WP_Customize_Manager::post_value()`.
Includes unit tests with assertions to check the reported issues and validate the fixes.
Fixes defect introduced in [35007].
See #32103.
Fixes#34738.
Built from https://develop.svn.wordpress.org/trunk@35724
git-svn-id: http://core.svn.wordpress.org/trunk@35688 1a063a9b-81f0-0310-95a4-ce76da25c4cd
