[TimePicker] Clock component is broken if minutesStep prop is not passed

[kiliancs]

Problem description

We are upgrading from 0.18.1 to 0.18.5 and found that the Clock component that was working well breaks now if the minutesStep prop is not passed.

The prop is not set as required and it doesn't have a default value. However, it is required to have a value because it is used in a calculation when the component mounts. Having an undefined minutesStep results in NaN showing up as the minutes.

This seems to have been introduced with 6ead93a, which means the problem first appeared in version 0.18.2.

Note that the format prop should also be required or have a default value, although this hasn't changed in recent versions.

I'd be happy to contribute a PR to fix this.

Link to minimal working code that reproduces the issue

[email protected] (no issues here): https://www.webpackbin.com/bins/-KoOpMlpk2KiDCRpOz7x
[email protected]: https://www.webpackbin.com/bins/-KoOpcYPkOmsoXsigImu

Versions

• Material-UI: 0.18.5
• React: 15.4.2
• Browser: Tested on Firefox 54.0.1

[oliviertassinari]

Closing for #4796