WebGL: Improve error message when a webglcontextlost event occurs?

[sjinno]

Currently when WebGL2RenderingContext is lost, wgpu seems to panic with DeviceError::OutOfMemory that displays a message saying Not enough memory left.

It would be helpful if wgpu panicked with DeviceError::Lost or something more relevant to the webglcontextlost event if possible instead of DeviceError::OutOfMemory.

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How to repro

I am not 100% certain about a consistent way to reproduce this issue, but for me (on macOS), changing screen resolution produces that error consistently.

Thank you!

[Wumpf]

device loss is actually speced out by now a bit here https://www.w3.org/TR/webgpu/#lose-the-device
according to this we need to implement a lost promise/callback

[jimblandy]

See also: #4163