Port the timeline ruler widget to Clutter
@jeff
Submitted by Jeff F.T. Assigned to Alex Băluț @aleb
Description
The ruler above the timeline is not a Clutter widget. This means it is not smoothly animated and in sync with the rest of the timeline (when zooming, scrolling or auto-scrolling during playback for example).
The trick/trap with this is that eventually, if Clutter gets replaced/merged by GTK, we'll have to port the whole thing back to pure GTK...
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=708491