Use wxDynamicCast() instead of IsKindOf() checks.

wxDynamicCast() is less verbose (due to the absence of "CLASSINFO") and more
compatible with the standard dynamic_cast<>, so prefer to use it when possible.

See #14356.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71624 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/renderer.cpp

@@ -145,7 +145,7 @@ static GdkWindow* wxGetGdkWindowForDC(wxWindow* win, wxDC& dc)
     GdkWindow* gdk_window = NULL;
 
 #if wxUSE_GRAPHICS_CONTEXT
-    if ( dc.IsKindOf( CLASSINFO(wxGCDC) ) )
+    if ( wxDynamicCast(&dc, wxGCDC) )
         gdk_window = win->GTKGetDrawingWindow();
     else
 #endif