KeyboardEvents do not populate key field

[classilla]

http://jsfiddle.net/nobuoka/WjJKk/

char should remain undefined as per Firefox 59 on my MacBook, but we are not populating key (it appears Unidentified). The other fields look correct.

This is probably what's wrong with http://calormen.com/jsbasic/ and possibly Facebook.

[classilla]

I don't think we're setting WidgetKeyboardEvent.mKeyNameIndex or WidgetKeyboardEvent.mCodeNameIndex in our code in widget/cocoa/nsChildView.mm since we don't use the TextInputHandler code.

[classilla]

I think we want to patch convertCocoaKeyEvent: to add this.

[classilla]

Tested fully working on both sites.