Add context menu enabling and disabling to wxWebView, all backends supported.

Closes #14789.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73326 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/webview_ie.h

@@ -271,8 +271,9 @@ private:
 class DocHostUIHandler : public wxIDocHostUIHandler
 {
 public:
-    DocHostUIHandler() {};
+    DocHostUIHandler(wxWebView* browser) { m_browser = browser; }
     ~DocHostUIHandler() {};
+
     virtual HRESULT wxSTDCALL ShowContextMenu(DWORD dwID, POINT *ppt,
                                               IUnknown *pcmdtReserved,
                                               IDispatch *pdispReserved);
@@ -319,6 +320,9 @@ public:
                                                IDataObject **ppDORet);
     //IUnknown
     DECLARE_IUNKNOWN_METHODS;
+
+private:
+    wxWebView* m_browser;
 };
 
 class wxFindPointers