Show how to handle files on command line in docview sample.

This is not totally obvious, so show how to do it, including the Mac-specific
MacNewFile() overriding part.

Closes #16816.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78498 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/docview/docview.h

@@ -13,6 +13,7 @@
 #define _WX_SAMPLES_DOCVIEW_DOCVIEW_H_
 
 #include "wx/docview.h"
+#include "wx/vector.h"
 
 class MyCanvas;
 
@@ -39,6 +40,8 @@ public:
     virtual void OnInitCmdLine(wxCmdLineParser& parser) wxOVERRIDE;
     virtual bool OnCmdLineParsed(wxCmdLineParser& parser) wxOVERRIDE;
 
+    virtual void MacNewFile() wxOVERRIDE;
+
     // our specific methods
     Mode GetMode() const { return m_mode; }
     wxFrame *CreateChildFrame(wxView *view, bool isCanvas);
@@ -68,6 +71,8 @@ private:
     // application object itself
     void OnAbout(wxCommandEvent& event);
 
+    // contains the file names given on the command line, possibly empty
+    wxVector<wxString> m_filesFromCmdLine;
 
     // the currently used mode
     Mode m_mode;