Remove indirection in checking propTypes

[gaearon]

TLDR: I’m removing react/lib/checkPropTypes import in favor of React.checkPropTypes public API access from renderer, and direct checkPropTypes access from the core.

Shared checkReactTypeSpec currently depends on react/lib/checkPropTypes which is gone in flat bundles. So this breaks in React Native sync process. In DOM, we currently ship two copies (in both React and ReactDOM flat bundles) but this breaks until RN is also a flat bundle. I could shim it but this seems like an easy fix because there’s a public API for this now.

The fix inside React package is just to import the internal checkPropTypes module directly.
The fix inside renderers is to use the public API (React.checkPropTypes).

[gaearon]

Hmm this seems like the wrong way to do it because of a circular dep. Easier to kill this module and do it differently I think.

[gaearon]

OK should be ready for review!

[acdlite]

We can remove checkPropTypes and import from prop-types/checkPropTypes instead.

[gaearon]

Means we technically start to depend on it?

[acdlite]

Yeah we can remove ReactPropTypes too. I started a PR to migrate all the tests accordingly but haven't finished yet, will wrap up post-15.5 (tomorrow).

[acdlite]

Although, because of flat bundles it would just be a dev dependency, right?

[gaearon]

Currently cjs flat bundles still use require for external deps (so that they can be deduped).

[gaearon]

I'll get this in for now so I can continue work on RN flat bundling, happy to change later.