Add hooks for capturing meaningful text info, gently.

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index a1404801f5b8a1f0953c4c519c3ce72dec6eebce..5513732300ddbd2bd267510106b33e98a036a72d 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -567,6 +567,7 @@ public:
     void setParsingState(ParsingState);
     bool parsing() const { return m_parsingState == Parsing; }
     bool isInDOMContentLoaded() const { return m_parsingState == InDOMContentLoaded; }
+    bool hasFinishedParsing() const { return m_parsingState == FinishedParsing; }
 
     bool shouldScheduleLayout() const;
     int elapsedTime() const;