Implement GetPageSource() and GetPageText()

interface/wx/webview.h

@@ -285,7 +285,7 @@ public:
     <a href="https://docs.microsoft.com/en-us/microsoft-edge/hosting/webview2">Edge WebView2</a>.
     It is available for Windows 7 and newer.
     The following features are currently unsupported with this backend:
-    virtual filesystems, custom urls, find, source code.
+    virtual filesystems, custom urls, find.
 
     This backend is not enabled by default, to build it follow these steps:
     - Visual Studio 2015, or newer, is required

src/msw/webview_edge.cpp

@@ -492,14 +492,16 @@ void wxWebViewEdge::Reload(wxWebViewReloadFlags WXUNUSED(flags))
 
 wxString wxWebViewEdge::GetPageSource() const
 {
-    // TODO: not implemented in SDK (could probably be implemented by script)
-    return wxString();
+    wxString text;
+    const_cast<wxWebViewEdge*>(this)->RunScript("document.documentElement.outerHTML;", &text);
+    return text;
 }
 
 wxString wxWebViewEdge::GetPageText() const
 {
-    // TODO: not implemented in SDK (could probably be implemented by script)
-    return wxString();
+    wxString text;
+    const_cast<wxWebViewEdge*>(this)->RunScript("document.body.innerText;", &text);
+    return text;
 }
 
 bool wxWebViewEdge::IsBusy() const