clearable and autoOk does not work on DateRangePicker

[gReis89]

Environment

Tech	Version
@material-ui/pickers	4.0.0-alpha.8
material-ui	4.10.2
React	16.12.0
Browser	chrome

Steps to reproduce

Use DateRangePicker with clearable and autoOk={false}

Expected behavior

The Clear button to be shown in the dialog, and the dialog to keep visible when user has selected both start and end dates

Actual behavior

There are no clear button and the autoOk prop is not keeping the modal open.

Live example

Example

[dmtrKovalenko]

We doesn't support clearable for desktop mode. And autoOk prop was removed

[oliviertassinari]

@dmtrKovalenko What do you think about the idea to add support for autoOk or something equivalent so that the change event is only fired once the current selection is validated?

[dmtrKovalenko]

We do have onAccept prop for that

[oliviertassinari]

We do have onAccept prop for that

@dmtrKovalenko I had forgotten about this one, I think that it's a different problem. I want to open an RFC to remove onAccept, it started in #1923 (comment).

There are three different cases to consider, that I think don't depend on the nature of the picker, it can be a combobox, a date picker, a time picker, a color picker, etc, it will always be the same:

1. Is the text field updated ahead of time? Basically, if we take the states of #1980. Is inputValue bound to value or selectedValue? In the Autocomplete, the prop for the behavior is autoComplete: https://material-ui.com/components/autocomplete/#playground
2. Is the value selected optimistically or not? Does the user need to confirm his choice? This is what the autoOk aims to determine. In the Autocomplete, the prop for the behavior is autoSelect: https://material-ui.com/components/autocomplete/#playground.
3. Does the popup close when a value is selected? The autoOk prop dictates the behavior. In the Autocomplete, the prop for the behavior is the disableCloseOnSelect prop: https://material-ui.com/components/autocomplete/#playground.

[gReis89]

if the autoOk and clearable aren't supported, is there some component that only exports the Calendars from DateRangePicker so we can implement extra functionalities in the popper as OK and Clear buttons?

I know that the lib exports Calendar and I'm already doing a similar implementation of a DatePicker with it, but I can't see any component in the DOCs that only export the double calendar used by DateRangePicker.