If the intent of WebNN is to produce an immutable MLCommandBuffer that can be read-only by WebGPU, then I would suggest we consider 1) renaming it to MLExternalCommandBuffer and 2) avoid overloading WebGPU Interop with requirements WebGPU does not follow: a command buffer with GPU commands being equal to a command buffer with non-GPU commands - by moving MLExternalCommandBuffer into a WebNN Interop section.

Alternatively, we could keep MLCommandBuffer (internal usage) but allow WebNN a means to submit (ex computeAsync). This would avoid breaking WebGPU and allow WebNN to have consistent GPU async support experience on both native (standalone) and web.

Thoughts?

@huningxin @wchao1115 @RafaelCintron