Add oEmbed support for mobile URL structures like mobile.twitter.com

[rachelmcr]

Expected behavior

I expect our oEmbeds to support the URL structures that these services use in mobile browsers. For example, Twitter uses mobile.twitter.com instead of twitter.com or www.twitter.com in mobile browsers.

Actual behavior

We only support Twitter embeds for twitter.com or www.twitter.com, not mobile.twitter.com:

https://github.com/WordPress/WordPress/blob/5eb2277dce2ee8a388cf86d112c5ae93809479a4/wp-includes/class-oembed.php#L58-L110

Tested on Nexus 9, Android 7.1.1, WPAndroid alpha-32

[maxme]

Looks like twitter supports it:

$ curl https://publish.twitter.com/oembed\?url=https://mobile.twitter.com/maximeb/status/793003939973267456
{"url":"https:\/\/twitter.com\/maximeb\/status\/793003939973267456","author_name":"Maxime","author_url":"https:\/\/twitter.com\/maximeb","html":"\u003Cblockquote class=\"twitter-tweet\"\u003E\u003Cp lang=\"en\" dir=\"ltr\"\u003EGreat post about \u003Ca href=\"https:\/\/twitter.com\/hashtag\/bitcoin?src=hash\"\u003E#bitcoin\u003C\/a\u003E and \u003Ca href=\"https:\/\/twitter.com\/hashtag\/ethereum?src=hash\"\u003E#ethereum\u003C\/a\u003E mining differences and how they affect hard forks \u003Ca href=\"https:\/\/t.co\/Qi1jGNNClA\"\u003Ehttps:\/\/t.co\/Qi1jGNNClA\u003C\/a\u003E \u003Ca href=\"https:\/\/t.co\/hchwRVRZ1m\"\u003Epic.twitter.com\/hchwRVRZ1m\u003C\/a\u003E\u003C\/p\u003E— Maxime (@maximeb) \u003Ca href=\"https:\/\/twitter.com\/maximeb\/status\/793003939973267456\"\u003EOctober 31, 2016\u003C\/a\u003E\u003C\/blockquote\u003E\n\u003Cscript async src=\"\/\/platform.twitter.com\/widgets.js\" charset=\"utf-8\"\u003E\u003C\/script\u003E","width":550,"height":null,"type":"rich","cache_age":"3153600000","provider_name":"Twitter","provider_url":"https:\/\/twitter.com","version":"1.0"}

But this must be fixed in WordPress before we can add the exception in the app.

[rachelmcr]

Ah, makes sense. I have a note for myself to test other oEmbed services to see if there are other similar URL structures that should be supported, and I'll open a core ticket to suggest a fix there first.

I'll close this issue for now, and we can reopen when WordPress supports it.