Add a general WordPress Backbone utility file

[koopersmith]

We've already added wp.template, but we could use a few more common Backbone helpers. Let's move these to a single wp-backbone file to start.

[koopersmith]

See [24358] and [24359].

[koopersmith]

In 24360:

Extract the base views from media.

See #24424.

[koopersmith]

In 24361:

Update the subview controller for the patterns found in Backbone 1.0.

Fixes #24424.

[koopersmith]

In 24366:

Alias media.template to wp.template. See #23263, #24424.

[koopersmith]

In 24367:

Add Backbone property to the wp-backbone namespace. See #24424.

[koopersmith]

In 24368:

Branch the generic JS utilities from the Backbone commands. See #24424.

[koopersmith]

In 24369:

Move XHR helpers from media to utils. See #24424.

[SergeyBiryukov]

Getting this on Edit Post screen after [24369] (with SCRIPT_DEBUG disabled):

TypeError: wp.xhr is undefined

The error breaks "Add Media" button (as ​reported in the forums), and also breaks the JS for switching post formats.

Looks like bumpbot didn't create wp-util.min.js.

[mindctrl]

I can't seem to replicate it at the moment, but when I first saw the issue with "Add Media", "Select Audio", etc. I was also having a problem, where on custom post types, the switcher was kicking me out to standard 'post' types and out of the custom post type. The link was missing the post_type=demo var. Just a heads up that maybe someone else can test.

[SergeyBiryukov]

Replying to mindctrl:

I can't seem to replicate it at the moment, but when I first saw the issue with "Add Media", "Select Audio", etc. I was also having a problem, where on custom post types, the switcher was kicking me out to standard 'post' types and out of the custom post type.

Related: #24360

[nacin]

In 24374:

Add wp-util.min.js. See #24424.

[sunnyratilal]

#24435 was marked as a duplicate.

[nacin]

In 24652:

Rename wp.xhr to wp.ajax to match admin-ajax.php (which it uses), jQuery.ajax (which it wraps), etc. see #24424.