dillon1000/react

Deprecate findDOMNode in StrictMode (#13841)

* Deprecate findDOMNode in StrictMode

There are two scenarios. One is that we pass a component instance that is
already in strict mode or the node that we find is in strict mode if
an outer component renders into strict mode.

I use a separate method findHostInstanceWithWarning for this so that
a) I can pass the method name (findDOMNode/findNodeHandle).
b) Can ignore this warning in React Native mixins/NativeComponent that use this helper.

I don't want to expose the fiber to the renderers themselves.