TapAction is a GestureAction-subclass that handles clicks and
tap gestures. It is meant to provide a replacement for ClickAction
using GestureAction:

• it handles events trasparently without capturing them, so that it
  can coexists with other GestureActions;

• the ::tap signal is not emitted if the drag threshold is exceeded;

• building upon GestureAction the amount of code is greatly reduced.

TapAction provides:

• tap signal, notifying users when a tap has been performed.

The image-content example program has been updated replacing its
ClickAction usage with TapAction.

https://bugzilla.gnome.org/show_bug.cgi?id=683948