Description of Change

Close #6330.

This PR adds a new MenuItem role shareMenu, that would turn a submenu into macOS share menu. There is also a new MenuItem.sharingItem property added, to specify which items to share.

const menu = Menu.buildFromTemplate([
  { role: 'windowMenu' },
  {
    role: 'shareMenu',
    sharingItem: {
      urls: [ 'https://github.com/electron/electron/issues/6330' ]
    }
  },
])
menu.popup(win)

There is also a new ShareMenu class added, which can create a top share menu directly. This is because MenuItem roles can only be applied on submenus, while it is very common to show a top share menu directly:

const menu2 = new ShareMenu({
  filePaths: [ __filename ]
})
menu2.popup(win)

Future extension

There could be a few possible feature requests about the share menu, like whether to show the "more" menu item, whether to hide certain items, callbacks to get notifications. Most of them can be achieved by adding new fields to the SharingItem structure.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation is changed or added
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Add support for showing macOS share menu.