Initialized mEnableRendering in constructors of nsDocumentViewer.cpp and nsPlugin.cpp to a default value of PR_TRU
Do EnableRefresh only if mEnableRendering is set to true in nsHTMLContentSink.cpp,nsXMLContentSink.cpp,
nsXMLContentSink.h
git-svn-id: svn://10.0.0.236/trunk@31441 18797224-902f-48f8-a5cc-f745e15eee43