Long click listener

[fishpowered]

Hi, I guess this is not strictly speaking a bug but using ChipView.OnLongClickListener doesn't fire when a chip is long clicked.

I had a look at how setOnChipClicked works and it seems be adding the listener to mContentLayout which is unfortunately private so I cannot add a long click listener myself. If there is any other way to achieve this please let me know but it'd be really useful to add long press events to the chips.

Thanks very much!