... It is const, renamed CopyTo, and invokes the create-on-demand factory in
the destination track; this means Track.cpp doesn't need to do that, and so
does not need TrackView.h
... non-intrusively in the Track suclasses, registering functions instead.
For each abstract factory function (of two), build a table of concrete factory
functions, paralleling the hierarchy of Track subclesses. Dispatch using
runt time type information in the Track objects.
... and eliminate some unnecessary calls to SubstitutePendingChangedTrack,
because the track and the substitute store Y and height in their shared
TrackView object.
Also make GetMinimizedHeight() virtual to avoid inclusion of TrackPanel.h in
TrackView.cpp.
... And Track no longer inherits TrackPanelCell, so be careful to rewrite
some dynamic_casts too to check instead for TrackView. Those casts won't fail
to recompile if not rewritten.
... but it does nothing yet.
This will be important to preserve undo/redo behavior of view changes, when
view state is moved out of the proper Track objects.
... except Experimental.h, but see preceding commit.
This is especially important in the header files.
Be sure there are no quiet changes of meaning when a header file is included
in a different context, not having seen Audacity.h. Rather include Audacity.h
even if redundantly.
Also, in some header files, move more inside the include-guard #ifdef-#endif
pair.
... except Audacity.h
This forces us to make each header contain all forward declarations or nested
headers that it requires, rather than depend on context.
... except Audacity.h; and in no others.
Do so even if Experimental.h gets multiply included, as in both the .h and
.cpp files.
This makes it easier to do a text scan to be sure there are no unintended quiet
changes of meaning because of omission of Experimental.h when the flag is
an enabled one.
Also move inclusions of Experimental.h earlier.
Also don't require Experimental.h to be preceded by Audacity.h to define
EXPERIMENTAL_MIDI_OUT correctly.
... so that we can use Track::SharedPointer without undefined behavior even on
tracks that don't yet belong to any TrackList.
Also fix the return type of function template TrackList::Add and remove some
casts.
... Also rewrote some of the existing event handling so all events from
TrackList are of the same, custom event class, and distinguishing addition
from resizing events, though this distinction is not yet used
