Introduce Core Widget: Video

[melchoyce]

This ticket introduces a new core widget for displaying videos.

See 32417#comment:136 for history.

Keep an eye on ​https://github.com/xwp/wp-core-media-widgets for development.

As I mentioned in the audio ticket (#39995), the widget would ideally handle both a locally hosted video file along with videos from major hosting platforms like YouTube, Vimeo, and VideoPress. One this is split into a standalone widget, we should evaluate whether it makes sense to handle embedding from third-parties in v1 or wait for a v2.

There's been previous exploration into embedding from third-party video services in #38172.

In 40640:

Widgets: Introduce media widgets for images, audio, and video with extensible base for additional media widgets in the future.

The last time a new widget was introduced, Vuvuzelas were a thing, Angry Birds started taking over phones, and WordPress stopped shipping with Kubrick. Seven years and 17 releases without new widgets have been enough, time to spice up your sidebar!

Props westonruter, melchoyce, obenland, timmydcrawford, adamsilverstein, gonom9, wonderboymusic, Fab1en, DrewAPicture, sirbrillig, joen, matias, samikeijonen, afercia, celloexpressions, designsimply, michelleweber, ranh, kjellr, karmatosed.
Fixes #32417, #39993, #39994, #39995.

In 40647:

Media: Clean-up some MediaElementJS CSS: no more needed after [40642].

See #40707, #32417, #39994, #39995, #30281.

In 40810:

Widgets: Introduce isHostedVideo method on VideoWidgetControl to allow plugins to extend for recognizing services beyond YouTube and Vimeo.

Also update jshint configuration in Gruntfile to include the widget scripts among the JS files linted.

Props timmydcrawford.
See #39994.
Fixes #40808.

In 40811:

Widgets: Remove unused JS variable to fix JSHint error introduced in [40640].

See #39994.

In 40812:

Widgets: clarify some context information for translators.

Props Italian polyglots team.
Amends [40640].
See #32417, #39993, #39994, #39995.

In 40813:

Media: Remove core embedding support for WMV and WMA files since MediaElement.js has discontinued supporting them.

Plugins may continue to add embedding support for these file formats by re-adding them via the wp_video_extensions and wp_audio_extensions filters while also implementing fallback rendering routines via the wp_video_shortcode_override and wp_audio_shortcode_override filters.

See #39994, #39995.
Fixes #40819.

In 40836:

Widgets: Ensure that audio and video files appear in media library browser upon upload.

Props timmydcrawford.
Amends [40640].
See #32417, #39994, #39995.
Fixes #40803.

In 40847:

Widgets: Normalize YouTube and Vimeo URLs in video shortcode (primarily for Video widget) to work around ME.js 2.22 bug.

Props timmydcrawford, jnylen0, westonruter.
See #32417, #39994.
Fixes #40866.

In 40892:

Media: Restrict appending loop parameter to Vimeo URLs specifically and not all external URLs in Video widget (via shortcode).

Fixes issue where Video widgets embedding external files fail to get recognized due to the presence of the loop param after the video filename, even though it has a recognized extension. Regardless, the loop param is only present to fix a Vimeo issue in ME.js 2.x.

Props timmydcrawford.
Amends [40640].
See #39686, #39994.
Fixes #40977.

In 40939:

Widgets: Forcibly limit Video widget to only accept oEmbed URLs from YouTube and Vimeo (for now).

Amends [40640].
Props timmydcrawford.
See #34115, #39994.
Fixes #40935.

In 41054:

Media: Restrict appending loop parameter to Vimeo URLs specifically and not all external URLs in Video widget (via shortcode).

Fixes issue where Video widgets embedding external files fail to get recognized due to the presence of the loop param after the video filename, even though it has a recognized extension. Regardless, the loop param is only present to fix a Vimeo issue in ME.js 2.x.

Merges [40892] into the 4.8 branch.
Props timmydcrawford.
Amends [40640].
See #39686, #39994.
Fixes #40977 for 4.8.1.

In 41056:

Widgets: Forcibly limit Video widget to only accept oEmbed URLs from YouTube and Vimeo (for now).

Merges [40939] onto 4.8 branch.
Amends [40640].
Props timmydcrawford.
See #34115, #39994.
Fixes #40935 for 4.8.1.