This is the core of the whole patch set.
Now GetPaintGeometry/PaintCaret figure out on their own almost all the state
they need every time we paint. So when caret flags change, all we need
to do is SchedulePaint. We don't need to fiddle with mDrawn and most of the
logic in DrawCaret is obsolete. (In fact, it was duplicated by GetGeometry
and friends, and we're removing that duplication.) EraseCaret, CheckCaretState
and UpdateCaretPosition are also obsolete.
We need to have GetPaintGeometry/PaintCaret choose the correct content node
and offset, either getting them from the Selection or using specific data set by
DrawAtPosition. This logic, plus a bit of other code shared between them, is
put into the helper GetFrameAndOffset.
--HG--
extra : rebase_source : e777605dd2507ae043e9f82d0a30e23aa06e0c12
343a7df89e