Added ImageCapture

[RoelofRuis]

• Added part of the ImageCapture API as per: https://developer.mozilla.org/en-US/docs/Web/API/MediaStream_Image_Capture_API

Does not include ImageCapture.getPhotoSettings() as its return value depends on a yet undocumented class.

Does not include ImageCapture.getPhotoCapabilities(), might be added later.

• Added ImageBitmap, required as return type for ImageCapture.grabFrame(): https://developer.mozilla.org/en-US/docs/Web/API/ImageBitmap

[japgolly]

This isn't supported in Firefox or Safari.
https://developer.mozilla.org/en-US/docs/Web/API/MediaStream_Image_Capture_API#imagecapture

Let's postpone this to 2.0 and see how we're gonna handle non-standard stuff.

[japgolly]

This isn't supported in Firefox or Safari.

So IIRC I think we said we're not gonna bother distinguishing between full and partial browser support, and that the onus would be on the user to know the (dynamic) status of the API they're calling. @armanbilge can you confirm? That was the plan right?

[armanbilge]

Yep! Decided in #514 (comment). So, we can bring this back to life!

[japgolly]

Awesome, thanks! On it....

[armanbilge]

I can't believe it!! We made it through every PR.

[japgolly]

💥 !