Support text input with system keyboard

[sienori]

Hi, I implemented text input using the system keyboard!

Changes

• Updated the Oculus Integration to use the system keyboard (first commit)
• Changed Addkeys() in GeckoViewPLugin.java to support non-English text
• Implemented a prototype of text input in BrowserView.cs.

https://user-images.githubusercontent.com/29514424/139308083-e325aee5-262a-42d1-a0d1-52365199904c.mp4

Known issues

• If you exit the system keyboard with a method other than the Confirm button (clicking outside the keyboard or the Close button), the focus will not return to the application. This is a bug in Oculus Quest build 33. https://forums.oculusvr.com/t5/Unity-Development/Keyboard-Overlay-broken-with-v33-update/m-p/885519
• I can't find a way to detect the input of backspace of the system keyboard.

[IanPhilips]

Hey sienori, thanks for the PR! Interesting you can't detect backspace, does _keyboard.text not pass the backspaced text? Or, in other words, what is the problem with not detecting the backspace - do we have to detect it and send the appropriate keycode?

[IanPhilips]

I also noticed you didn't add the rebuilt plugin, so I'll add that. And maybe that's a better trust model perhaps standard with these situations. I just built the project on my Oculus Go and no keyboard is showing up. That may just be an issue with Oculus Go though, I don't have a quest to try it out with. Do you have a Go to try it out in? Are there any configuration steps needed in ether scene or should it 'just' work?

[Abhishek8Chili]

Will try this on a quest today and report.

[IanPhilips]

any luck @Abhishek8Chili ?

[clovelt]

This works wonderfully! All known issues have been fixed in subsequent Oculus updates, as of v35 both unfocus keyboard and backspace works perfectly.

[IanPhilips]

Thanks for submitting @sienori and thanks for testing it @clovelt!