Only populate line number in case parsing synchronously.

Source/core/dom/ScriptableDocumentParser.cpp

 /*
  * Copyright (C) 2010 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 
 ScriptableDocumentParser::ScriptableDocumentParser(Document& document, ParserContentPolicy parserContentPolicy)
     : DecodedDataDocumentParser(document)
     , m_wasCreatedByScript(false)
     , m_parserContentPolicy(parserContentPolicy)
 {
     if (!pluginContentIsAllowed(m_parserContentPolicy) && (!document.settings() || document.settings()->unsafePluginPastingEnabled()))
         m_parserContentPolicy = allowPluginContent(m_parserContentPolicy);
 }
 
+bool ScriptableDocumentParser::isParsingAtLineNumber() const
+{
+    return isParsing() && !isWaitingForScripts() && !isExecutingScript();
+}
+
 };