Document wxDocument::DeleteContents().

This method purpose was not quite clear as it was only mentioned in passing in
documentation of OnCloseDocument() but not really documented itself.

Also don't call it from wxDocument dtor as this is useless: the user-defined
overridden version will never be called from here and the base class version
does nothing.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64299 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/docview.h

@@ -129,6 +129,8 @@ public:
     // deletes the document if this is there are no more views.
     virtual void OnChangedViewList();
 
+    // Called from OnCloseDocument(), does nothing by default but may be
+    // overridden. Return value is ignored.
     virtual bool DeleteContents();
 
     virtual bool Draw(wxDC&);

interface/wx/docview.h

@@ -1141,6 +1141,18 @@ public:
     */
     virtual bool DeleteAllViews();
 
+    /**
+        Virtual method called from OnCloseDocument().
+
+        This method may be overridden to perform any additional cleanup which
+        might be needed when the document is closed.
+
+        The return value of this method is currently ignored.
+
+        The default version does nothing and simply returns @true.
+     */
+    virtual bool DeleteContents();
+
     /**
         Returns a pointer to the command processor associated with this
         document.
@@ -1258,10 +1270,10 @@ public:
     /**
         This virtual function is called when the document is being closed.
 
-        The default implementation calls DeleteContents() (an empty
-        implementation) and sets the modified flag to @false. You can override
-        it to supply additional behaviour when the document is closed with
-        Close().
+        The default implementation calls DeleteContents() (which may be
+        overridden to perform additional cleanup) and sets the modified flag to
+        @false. You can override it to supply additional behaviour when the
+        document is closed with Close().
 
         Notice that previous wxWidgets versions used to call this function also
         from OnNewDocument(), rather counter-intuitively. This is no longer the

src/common/docview.cpp

@@ -135,8 +135,6 @@ bool wxDocument::DeleteContents()
 
 wxDocument::~wxDocument()
 {
-    DeleteContents();
-
     delete m_commandProcessor;
 
     if (GetDocumentManager())