Add wxActiveXContainer::QueryClientSiteInterface to allow customisation of ActiveX controls.

Closes #13784.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70361 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/msw/ole/activex.h

@@ -267,7 +267,7 @@ public:
     };
 
     wxIMPLEMENT_DYNAMIC_CLASS(wxPDFMediaBackend, wxMediaBackend);
-    
+
     // Put this in one of your existing source files and then create a wxMediaCtrl with
     wxMediaCtrl* mymediactrl = new wxMediaCtrl(this, "myfile.pdf", wxID_ANY,
                                             wxDefaultPosition, wxSize(300,300),
@@ -297,5 +297,18 @@ public:
             Interface of ActiveX control.
     */
     wxActiveXContainer(wxWindow* parent, REFIID iid, IUnknown* pUnk);
+    /**
+        Queries host's site for interface.
+
+        @param iid
+            The iid of the required interface.
+        @param _interface
+            Double pointer to outgoing interface. Supply your own interface if desired.
+        @param desc
+            The description of the outgoing interface.
+        @return bool
+            Return true if interface supplied else return false.
+    */
+    virtual bool QueryClientSiteInterface(REFIID iid, void **_interface, const char *&desc);
 };