Proposal: Generate GUID for projected runtimeclasses via attribute

[asklar]

Summary

Projection should generate a Guid member on runtimeclasses annotated with [ComOutOfProcClsId(...)] with its value

1. SDK annotates the runtimeclass with an attribute, and
2. cswinrt should read from that attribute to generate a Guid member so that you can say typeof(theRuntimeClass).GUID to refer to the CLSID

Rationale

Needed to make OOP APIs usable without additional helper libraries

Important Notes

No response

Open Questions

No response