[RFR] Add options prop to TabbedShowLayout

[lucas2595]

After facing the same problems as #2317, this PR allows to pass props through <TabbedShowLayout> to material-ui's <Tabs>. This way the user can enable all the different Tabs modes (such as scrollable, centered), and pass other props that might be useful. This is done through the options prop in <TabbedShowLayout>.

[fzaninotto]

Thanks for your PR. I have a better idea to solve this problem: add a tabs prop that defaults to the <Tabs> component as it is today, to let developers override it. See e.g. the body prop of the <Datagrid> component as an example.

[lucas2595]

That indeed sounds better. Just made another commit to it implementing that.

[fzaninotto]

Please make this PR against next instead of master as it's a new feature.

[lucas2595]

Sorry about the messed up history, first time forking and making a PR on github here. All those force-pushes were to fix a rebase gone wrong. Should I redo it from scratch to clean things up?

[fzaninotto]

I can squash and merge, don't worry about that.

[fzaninotto]

Terrific, thanks a lot!

[MROFerreiro]

Is this really working? I tried to use an options object with props defined in material-ui tabs component in <TabbedShowLayout> like: <TabbedShowLayout options={{scrollable=true}} /> but it doesn't work. How is this supposed to be used?
For what I saw in source code, there is no options props treated by <TabbedShowLayout> neither in <TabbedShowLayoutTabs> the new tabs. Am I missing something?
I also tried to import <TabbedShowLayoutTabs> and give it the scroll option, but is isn't exported at framework level.

[lucas2595]

I'm sory @MROFerreiro, the PR title became misleading after it was decided to use a tabs prop in <TabbedShowLayout> like: <TabbedShowLayout tabs={<TabbedShowLayoutTabs/>}> (where <TabbedShowLayoutTabs/> is the old tabs component that was being used before this PR) instead of the options props suggestion.
For what you're trying to do, you can either use <TabbedShowLayout tabs={<TabbedShowLayoutTabs scrollable={true}/>}> (since the props passed to TabbedShowLayoutTabs are passed to the material-ui's Tabs inside it), or you can create your own tabs component, and then use it like: <TabbedShowLayout tabs={<MyCustomTabs/>}>.
@fzaninotto should I edit the PR's title to prevent this confusion?

[MROFerreiro]

Currently is not possible to use your solution with <TabbedShowLayoutTabs> since it is not export in index of details simply adding export {default as TabbedShowLayoutTabs} from './TabbedShowLayoutTabs' would fix it, currently I copied your implementation to a custom component and used it. Seems fine, but I need to do some corrections on my side in order for it to work properly.
That said, @fzaninotto, since is a simple hotfix I don't think is needed to do another merge request.

[fzaninotto]

Please open a new PR to export and document TabbedShowLayoutTabs

[MROFerreiro]

@lucas2595 can you do it? Since you were the one that build this feature you would produce better docs than I and faster. Don't forget the export of the new Tabs component. 😃

[lucas2595]

Sure thing, @MROFerreiro. Sorry for the delay, got caught up with with some other stuff in the past days. I'll do it right now.