Add GetPageText to MSW IE and to GTK WebKit. Add stub for OSX and document.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/SOC2011_WEBVIEW@68250 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/webview_webkit.h

@@ -110,6 +110,7 @@ public:
     virtual wxString GetCurrentURL();
     virtual wxString GetCurrentTitle();
     virtual wxString GetPageSource();
+    virtual wxString GetPageText();
     //We do not want to hide the other overloads
     using wxWebView::SetPage;
     virtual void SetPage(const wxString& html, const wxString& baseUrl);

include/wx/msw/webview_ie.h

@@ -63,6 +63,7 @@ public:
     virtual void Reload(wxWebViewReloadFlags flags = wxWEB_VIEW_RELOAD_DEFAULT);
 
     virtual wxString GetPageSource();
+    virtual wxString GetPageText();
 
     virtual bool IsBusy();
     virtual wxString GetCurrentURL();

include/wx/osx/webview_webkit.h

@@ -56,6 +56,7 @@ public:
     virtual void Reload(wxWebViewReloadFlags flags = wxWEB_VIEW_RELOAD_DEFAULT);
     virtual void Stop();
     virtual wxString GetPageSource();
+    virtual wxString GetPageText() { return ""; }
     virtual void SetPageTitle(const wxString& title) { m_pageTitle = title; }
     virtual wxString GetPageTitle(){ return m_pageTitle; }
 

include/wx/webview.h

@@ -222,6 +222,7 @@ public:
      *         shown
      */
     virtual wxString GetPageSource() = 0;
+    virtual wxString GetPageText() = 0;
 
    /**
      * Get the zoom factor of the page