Use WithStyles in runtime (instead of just as an HOC) -- allow for dynamic styles

[buob]

• This is not a v0.x issue.
• I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior

I'm not exactly sure how the contract would be, but I would like to use WithStyles in runtime, so I can modify the styles that I pass to it in runtime.

<WithStyles styles={someDynamicJSS}>
  <div />
</WithStyles>

Current Behavior

(I believe) I can only call the HOC, locking in the styles that are passed at build time.

withStyles(staticStyles)(MyComponent)

Examples

I'm assuming it wouldn't be quite as simple as exporting the WithStyles class, assuming it's not exported right now gives me the impression it's not possible as a feature today.

Context

We are building a system that allows users to create pages, and they can select "stylesheets" of sorts that are different collections of JSS so they can dynamically change the look of the page. They will eventually be able to provide their own JSS.

[oliviertassinari]

@buob Check the follow resources out:

• https://material-ui.com/css-in-js/basics/#adapting-higher-order-component-api
• [withStyles] Add the ability to get the component's props from within the style object #7633 (comment)

[oliviertassinari]

@buob You are going to like this API: https://next.material-ui.com/css-in-js/basics/#adapting-hook-api.