D25700: [KHistoryComboBox] Add method to set an icon provider

[Nicolas Fella]

nicolasfella added a task: T12310: Kill KUrlPixmapProvider.

REPOSITORY
  R284 KCompletion

REVISION DETAIL
  https://phabricator.kde.org/D25700

To: nicolasfella, #frameworks
Cc: kde-frameworks-devel, LeGast00n, GB_2, michaelh, ngraham, bruns