Always set background colour prior to any HTML rendering (this fixes assert in GTK2 build because BgColor of wxHtmlRenderingState was unset=invalid)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@24520 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/winpars.cpp

@@ -187,6 +187,9 @@ void wxHtmlWinParser::InitParser(const wxString& source)
 #endif
 
     m_Container->InsertCell(new wxHtmlColourCell(m_ActualColor));
+    m_Container->InsertCell(
+            new wxHtmlColourCell(GetWindow()->GetBackgroundColour(),
+                                 wxHTML_CLR_BACKGROUND));
     m_Container->InsertCell(new wxHtmlFontCell(CreateCurrentFont()));
 }