Fix crash in wxMDIParentFrame dtor after taskbar branch merge.

wxFrame::m_taskBarButton needs to be initialized in its Init(), not Create(),
which is not necessarily used by the derived classes such as wxMDIParentFrame,
resulting in a guaranteed crash when deleting an uninitialized pointer later
in wxFrame dtor.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77688 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix wxCALL_FOR_EACH() to work with more than 2 arguments with MSVC.

Due to a bug in MSVC handling of __VA_ARGS__ (see
https://connect.microsoft.com/VisualStudio/feedback/details/380090/variadic-macro-replacement)
wxCALL_FOR_EACH() didn't work correctly as long as more than two arguments
were used with it.

Work around the bug by protecting __VA_ARGS__ from being incorrectly passed as
a single token to the macro being called on every step: this was already done
for wxCALL_FOR_EACH itself with wxCALL_FOR_EACH_, but we need to do it for all
the helper macros too.

Also add a test checking that this does, actually, work.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77689 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Avoid creating wxGraphicsContext in the drawing sample unnecessarily.

This is not only wasteful, but creating a Direct2D surface associated with a
wxDC makes it impossible to paint on the DC using GDI functions, so this
completely broke the initial display in the sample.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77690 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Split screen selection in a separate menu in the drawing sample.

No real changes, just make the "File" menu (which was also renamed to
"Drawing" as it has nothing to do with files) less long by splitting off the
screen selection in a separate menu.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77691 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Allow selecting wxGraphicsRenderer to use in the drawing sample.

In particular, allow switching between GDI+ and Direct2D under Windows, which
is very convenient for comparing the rendering results.

This can also be useful when using Cairo.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77692 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix memory leak when creating new Direct2D-based wxGraphicsContext.

ID2D1DCRenderTarget was leaked every time a wxD2DContext was created because a
raw pointer was given to wxCOMPtr<> which didn't take its ownership.

Use wxCOMPtr instead of the raw pointer to fix this and also fix more rare but
still possible leak in case of error.

This fixes out of memory errors and crashes in the drawing sample after a few
seconds of constant window resizing/repainting.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77693 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Return to using GDI+ by default in wxGraphicsContext under MSW.

Unfortunately Direct2D-based wxGraphicsRenderer is not ready for use yet as it
doesn't draw lines with width 0, which are commonly used.

The code using it in GetDefaultRenderer() will need to be restored when this
bug is fixed.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77694 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775