Ajax issue in the customizer when previewing a different theme

[Fab1en]

When a theme is activated, and another one is previewed using the customizer live preview, ajax requests are run against the old theme, not the one being previewed.

The easiest way to see this issue is to use the Header Image cropping function included in core.

1. Install and activate a theme that has no custom-header feature (for example ​Modern Estate)
2. Go to the customizer, click on the change button to choose a new theme (for example, TwentyFifteen
3. Use the Header Image panel to select and crop an image
4. You get the following error : There has been an error cropping your image.
5. Activate TwentyFifteen and crop the same image again : error has disappeared

If a theme defines specific ajax actions, those actions will not be available in the live preview until the theme is really activated.

[celloexpressions]

Probably should add the theme previewing logic to ajax calls, although I thought it already was. Needs investigating.

[westonruter]

Need to make sure the theme parameter is included in the Ajax requests.

[westonruter]

Note that generally in Core, Ajax requests initiated from the preview do not get the Customizer state applied. This has, however, been implemented in the transactions patch via jQuery.prefilter() to inject the Customizer transaction UUID. So this issue will be resolved there.

However, this issue is specific to an Ajax request created in the Customizer pane, and so I think it is included in the scope of transactions.

[rittesh.patel]

Patch to fix #32783

[faishal]

Without ajaxprefilter approach, by allowing crop ajax data to be overridden

[westonruter]

I like that approach, to hook into the underlying doCrop function, and extending an exposed doCropArgs to inject the additional args.

[westonruter]

@wonderboymusic thoughts on extending the wp.media.controller.Cropper.prototype.doCrop in this way?

[westonruter]

Minor style tweaks

[westonruter]

In 36866:

Customize: Fix image cropping when doing live preview of theme switches.

Ensure that the Customizer gets bootstrapped with the pre-activated theme supplied in the custom-header-crop admin ajax requests.

Props faishal, rittesh.patel.
Fixes #32783.

[pento]

[36866] updated media-views.js, but didn't apply the change to controllers/cropper.js, which is causing grunt precommit:js to incorrectly remove the change from media-views.js.

[pento]

In 36931:

Customize: Update cropper.js to match changes in [36866].

media-views.js was updated, but the changes weren't added to cropper.js, which caused the grunt precommit:js job to incorrectly remove the changes from media-views.js.

Fixes #32783.