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.


git-svn-id: https://develop.svn.wordpress.org/trunk@36866 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/customize-controls.js

@@ -2346,6 +2346,10 @@
 				api.HeaderTool.UploadsList,
 				api.HeaderTool.DefaultsList
 			]);
+
+			// Ensure custom-header-crop Ajax requests bootstrap the Customizer to activate the previewed theme.
+			wp.media.controller.Cropper.prototype.defaults.doCropArgs.wp_customize = 'on';
+			wp.media.controller.Cropper.prototype.defaults.doCropArgs.theme = api.settings.theme.stylesheet;
 		},
 
 		/**

src/wp-includes/js/media-views.js

@@ -282,8 +282,10 @@ Cropper = wp.media.controller.State.extend({
 		toolbar:     'crop',
 		content:     'crop',
 		router:      false,
+		canSkipCrop: false,
 
-		canSkipCrop: false
+		// Default doCrop Ajax arguments to allow the Customizer (for example) to inject state.
+		doCropArgs: {}
 	},
 
 	activate: function() {
@@ -367,11 +369,15 @@ Cropper = wp.media.controller.State.extend({
 	},
 
 	doCrop: function( attachment ) {
-		return wp.ajax.post( 'custom-header-crop', {
+		return wp.ajax.post( 'custom-header-crop', _.extend(
+			{},
+			this.defaults.doCropArgs,
+			{
 				nonce: attachment.get( 'nonces' ).edit,
 				id: attachment.get( 'id' ),
 				cropDetails: attachment.get( 'cropDetails' )
-		} );
+			}
+		) );
 	}
 });