Dependency Reduction?

[AldaronLau]

I was looking at cargo tree and wondering if there's places for improvement in reducing dependencies. I came up with the following things:

• I'm wondering if it's possible to make raw-window-handle an optional dependency (say if the programmer doesn't need a window).
• Dependencies naga and codespan-reporting always pull in termcolor, which should be unnecessary
• The smallvec and arrayvec dependencies do almost the same thing, could possibly use tinyvec for both use cases
• The profiling crate could also be optional

I don't know if all of these are a good idea, but I'd be willing to work on any of them.

[kpreid]

These two are probably only relevant if wanting to remove dependency count rather than size:

• raw-window-handle is very lightweight since it only provides types (that contain *mut c_void pointers for the most part).
• profiling only depends on profiling backends requested by features — its purpose is essentially to be the mechanism by which profiling instrumentation is conditionally compiled.

[cwfitzgerald]

Smallvec is a much more complicated bit of kit - it has non-zero overhead over a Vec/ArrayVec, so it's a specialized tool that we need in certain situations.

[teoxoy]

codespan-reporting (used in wgpu to display naga's validation errors) depends on termcolor, so making naga's usage of termcolor optional won't change wgpu's tree.

I double checked wgpu's tree and it seems besides #3502 there aren't other opportunities to remove other dependencies.

I think we can close this for now.