In `media_buttons()`, add a static var `$instance` to increment the `id` attribute of `insert-media-button-%d` on each call.

Props ericlewis.
Fixes #28090.

Built from https://develop.svn.wordpress.org/trunk@28837


git-svn-id: http://core.svn.wordpress.org/trunk@28641 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Race conditions can cause `.uploader-window` to be visible with opacity of `0`. It will cause the user to have to refresh the page or inspect the element to hide it. Add a delay in `wp.media.view.UploaderWindow.hide()` to ensure that the uploader window is indeed hidden.

Props kovshenin.
Fixes #27341.

Built from https://develop.svn.wordpress.org/trunk@28838


git-svn-id: http://core.svn.wordpress.org/trunk@28642 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Dynamically prepend screen reader text to the attachment filters dropdown and the search box in the media modal.

Props SergeyBiryukov.
Fixes #25102.

Built from https://develop.svn.wordpress.org/trunk@28839


git-svn-id: http://core.svn.wordpress.org/trunk@28643 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `wp_localize_script()`, instantiate the `$wp_scripts` global instead of bailing when it is called before `wp_enqueue_scripts`. This allows `wp_enqueue_media()` to be called on the front end with no JS errors. 

Props ericlewis.
Fixes #24724.

Built from https://develop.svn.wordpress.org/trunk@28840


git-svn-id: http://core.svn.wordpress.org/trunk@28644 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add mime support for 3gp, 3g2 and 3gpp video formats. These are not supported by MediaElement or the WP media shortcodes, just an FYI.

Props azaozz, m_uysl.
Fixes #23380.

Built from https://develop.svn.wordpress.org/trunk@28841


git-svn-id: http://core.svn.wordpress.org/trunk@28645 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Apply a subtle semi-transparent border to images in the media list table to avoid the "white on white (like a polar bear in Antarctica)" problem.

Props ericlewis.
Fixes #15860.

Built from https://develop.svn.wordpress.org/trunk@28842


git-svn-id: http://core.svn.wordpress.org/trunk@28646 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Only apply a subtle semi-transparent border to attachments that are images in the media list table.

See [28842], #15860.


Built from https://develop.svn.wordpress.org/trunk@28843


git-svn-id: http://core.svn.wordpress.org/trunk@28647 1a063a9b-81f0-0310-95a4-ce76da25c4cd