Tenor GIF picker for Gutenberg editor

[ngoctr]

This added Tenor Picker support for Gutenberg editor as part of #13803.

Testing

First steps

1. Register your Tenor developer API here: https://tenor.com/gifapi
2. Check out this branch
3. Put your API Key into .configure-files/wpcom_app_credentials (TENOR_API_KEY line)
4. Run rake dependencies
5. Build and run

Verify Tenor support in Gutenberg Editor

1. Go to Site -> Posts
2. Tap any Post to edit it, if you are using Classic (Aztec) Editor, you will need to switch to Block Editor.
3. Tap the + button at the bottom left corner
   
4. Choose an Image or Gallery block
   
5. Tap ADD IMAGE button to activate the media picker
   
6. Choose Free GIF Library
7. Search and select the GIF(s) you want to insert, then tap Add button at the bottom right corner
   
8. Verify the selected GIF(s) have been added into the Post

There are other flows in the Block Editor also involved the Tenor Picker that you should also make tests:

• Replace an image:
  
• Media & Text block:
  

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered adding accessibility improvements for my changes. (Will be in a separate PR)
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary. (Will be in a separate PR)

[ScoutHarris]

Hey @ngoctr .

Sometimes when previewing a post while GIFs are loading, some GIFs don't end up in published post.

• While editing a post, select several GIFs.
• While they are loading, preview the post.
• Notice not all the GIFs appear in the preview.
• Close the preview and return to the post.
• After all the GIFs have loaded, preview again.
• Notice not all the GIFs are present.
• Publish the post.
• Notice not all the GIFs are present.
• Edit the post.
• This does show all the GIFS, including the ones missing from the published post.

[ngoctr]

@ScoutHarris I noticed the same issue with Stock Photos too, it's not just happened only with GIFs. There are weird URLs in my debug log:
2020-04-16 10:56:07:539 WordPress[40899:911143] Unable to download image for attachment with url = Optional(https://i0.wp.com////Users/winter/Library/Developer/CoreSimulator/Devices/C2722B0E-AA32-48D5-A915-548DBFFD6216/data/Containers/Data/Application/BCB3B647-6AE5-4D5C-B753-5157A7EFC3D1/Library/Caches/Media/thumbnail-p26-1792x1792.jpeg?quality=80&w=1792). Details: Optional("The operation couldn’t be completed. (WordPress.ImageDownloaderError error 0.)")

[ScoutHarris]

I noticed the same issue with Stock Photos too, it's not just happened only with GIFs.

Aaaahh. Would you mind creating an issue in the gutenburg repo (if one doesn't already exist) and we'll reference that here.

[ngoctr]

I noticed the same issue with Stock Photos too, it's not just happened only with GIFs.

Aaaahh. Would you mind creating an issue in the gutenburg repo (if one doesn't already exist) and we'll reference that here.

Sure, I will do that. If I do update the Post before previewing, then everything is working ;-)

[ScoutHarris]

With the known issue with some media not loading, this looks fine.

Thanks @ngoctr !

[ScoutHarris]

If I do update the Post before previewing, then everything is working

Well you know very well people are not that patient. How do you think I found it? 😆

[ngoctr]

If I do update the Post before previewing, then everything is working

Well you know very well people are not that patient. How do you think I found it? 😆

Haha, I see 😃 Thanks @ScoutHarris for approving this.