Replace wxLogError() with wxLogDebug() in wxGTK wxDVC code.

The type mismatch between the value returned from the model and the one
returned by the control cannot be due to any user action, so it is quite
useless to show it to the user, it is only relevant for the developers.

Use wxLogDebug() and not wxASSERT() because asserting in a wxEVT_PAINT
callback would result in a crash due assert reentrancies.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78292 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Don't warn if model cell value is empty in wxGTK wxDVC.

Make wxGTK consistent with the generic version and, generally speaking, more
reasonable by allowing to leave any cell empty by just not filling in the
wxVariant in the model GetValue() for it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78293 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Remove unnecessary methods of wxCocoaOutlineDataSource.

{append,remove}Child() were never used, remove them to make it easier to
remove the use of "children" array itself later (see #16740).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78294 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Refactor type checks in wxOSX wxDVC implementation.

Check the type in one place only, before calling MacRender() instead of doing
it in each and every implementation of it.

Also replace wxFAIL_MSG() with wxLogDebug() as the former resulted in a crash
due to assert reentrancy, as usual when asserting inside a wxEVT_PAINT handler
which is constantly called all the time, and so wasn't particularly useful.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78295 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Don't warn if model cell value is empty in wxOSX wxDVC.

This follows similar change to wxGTK a few commits ago and makes wxOSX
consistent with the generic version.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78296 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Don't try setting width before column is added to wxOSX wxDVC.

This is not going to work anyhow and the width will be really set later, when
InsertColumn() is called.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78297 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775