Initial framework for compute shaders on WebGPU

[mvaligursky]

Initial framework, allowing creation and dispatch of WebGPU computer shaders. Note that support for passing data in / out of the compute shader is not yet supported.

All API is currently private, but expected public API:

• Shader options object passed to constructor accepts compute shader source code
• Compute - new class wrapping an instance of the compute shader along with its parameters (buffers, textures)

Example of its use:

const shader = new Shader(device, {
    name: 'ComputeShader',
    shaderLanguage: SHADERLANGUAGE_WGSL,
    cshader: `
        @compute @workgroup_size(8, 8)
        fn main(@builtin(global_invocation_id) global_id : vec3u) {
        }
    `
});

const compute = new Compute(device, shader);
compute.dispatch(4);