Inherit const members in constructors

[saschanaz]

Fixes #531

This doesn't look very ideal as this basically copies everything, but not sure what should be done for those inline type literals.

Maybe we can introduce new (InterfaceName)Constants interfaces and use them:

declare var MyClass: {
  prototype: MyClass;
  new(): MyClass;
} & MyClassConstants;

What do you think? @mhegazy

[mhegazy]

that looks like a lot of duplication really. Adding a new interface per variable does not seem much better either with the global scope pollution; the intersection does not look attractive either.

I would say the issue here is that these all should be defined as classes instead of variable+interface pairs, this way you get the static inheritance for free.

I suggest we shelve this until we have updated the DOM to use the webidl as a source first, then revisit the class generation question.

[saschanaz]

I suggest we shelve this until we have updated the DOM to use the webidl as a source first

Actually this becomes a blocker when WebGL has moved every constant from interface WebGLRenderingContext to interface mixin WebGLRenderingContextBase. This way the constructor loses all constants when without static inheritance.

Should we just add a special check for WebGLRenderingContext case as a temporary solution?

Edit: Classes won't help the WebGL case as mixins are not classes.
Edit2: Hmm, maybe we can generally copy the constants for mixins (as IMO currently it's only for the WebGL case), and defer others for now.

[saschanaz]

This PR now only covers mixin cases.