Add option to wxWebViewHandler to set a custom security URL

This will be used by wxWebViewIE to modify the security URL and domain when
parsing a URL.

include/wx/webview.h

@@ -89,12 +89,16 @@ enum wxWebViewNavigationActionFlags
 class WXDLLIMPEXP_WEBVIEW wxWebViewHandler
 {
 public:
-    wxWebViewHandler(const wxString& scheme) : m_scheme(scheme) {}
+    wxWebViewHandler(const wxString& scheme)
+        : m_scheme(scheme), m_securityURL() {}
     virtual ~wxWebViewHandler() {}
     virtual wxString GetName() const { return m_scheme; }
     virtual wxFSFile* GetFile(const wxString &uri) = 0;
+    virtual void SetSecurityURL(const wxString& url) { m_securityURL = url; }
+    virtual wxString GetSecurityURL() const { return m_securityURL; }
 private:
     wxString m_scheme;
+    wxString m_securityURL;
 };
 
 extern WXDLLIMPEXP_DATA_WEBVIEW(const char) wxWebViewNameStr[];

interface/wx/webview.h

@@ -252,6 +252,20 @@ public:
         @return The name of the scheme, as passed to the constructor.
     */
     virtual wxString GetName() const;
+
+    /**
+        Sets a custom security URL. Only used by wxWebViewIE.
+
+        @since 3.1.5
+    */
+    virtual void SetSecurityURL(const wxString& url);
+
+    /**
+        @return The custom security URL. Only used by wxWebViewIE.
+
+        @since 3.1.5
+    */
+    virtual wxString GetSecurityURL() const;
 };
 
 /**