CHE-3896 add the needed methods for Webview API

[olexii4]

Add the needed methods for Webview API.

How to test these changes with a test webview-sample:

1. With Theia https://youtu.be/aN6MrDkkQMs
2. With VS Code https://youtu.be/Mh3I6ypdSQU

#3896

Signed-off-by: Oleksii Orel oorel@redhat.com

[akosyakov]

@olexii4 please think how we will test it, e.g. provide a sample VS Code extension, play with it in VS Code to learn requirements, describe what to do to verify that APIs work in different scenarios, make the screencast showing it

[olexii4]

The test plugin
https://github.com/olexii4/webview-sample.git

I am working on the video.

[olexii4]

https://youtu.be/aN6MrDkkQMs
https://youtu.be/Mh3I6ypdSQU

[akosyakov]

It does not really work for me: Open 3 files in the same tab group and then try to use the sample extension to open in 3rd view position. It opens in the same group, not even trying to create a new one.

[olexii4]

It does not really work for me: Open 3 files in the same tab group and then try to use the sample extension to open in 3rd view position. It opens in the same group, not even trying to create a new one.

I tried to implement the same behavior as in VSCode. But I can fix it

[akosyakov]

I tried to implement the same behavior as in VSCode. But I can fix it

let me try the same in VS Code

[akosyakov]

@olexii4 in the same VS Code it is based on editor groups (tab groups in Theia), not individual editors like in this PR.

See:

Here 3 editors in first group and I'm trying to open the webview in 3rd group, so VS Code opens a new group to right.

[olexii4]

@akosyakov Now I see. Previously I tested VS Code with two editor groups (tab groups) and behavior was different:
https://youtu.be/y7K6Pwdsoqw
Ok. I will fix it

[akosyakov]

@olexii4 It looks like a bug to me. It only happens if the first group has a focus, if you remove a focus (select a navigator) it will open a new group in VS Code as well. Could you file an issue against VS Code to ask whether it is a bug, no need to point to this PR? Maybe we are overlooking something.

[olexii4]

@akosyakov Totally agree with you. It is like a bug for me too.
Yes, I could file an issue against VS Code to ask whether it is a bug.

[olexii4]

@akosyakov WDYT?

[akosyakov]

It works good now 👍

Please have a look at comment. I have concerns that it won't work with multiple webviews.