Revert of Revert "Moved text decoding to the parser thread"

Source/core/html/parser/XSSAuditor.h

Index: Source/core/html/parser/XSSAuditor.h
diff --git a/Source/core/html/parser/XSSAuditor.h b/Source/core/html/parser/XSSAuditor.h
index db2655f4a8a7678e81452b7cdc6325c634fa876e..37e463c8d2bb6373d906d83edddf85227a89cce7 100644
--- a/Source/core/html/parser/XSSAuditor.h
+++ b/Source/core/html/parser/XSSAuditor.h
@@ -64,6 +64,8 @@ public:
     PassOwnPtr<XSSInfo> filterToken(const FilterTokenRequest&);
     bool isSafeToSendToAnotherThread() const;
 
+    void setEncoding(const WTF::TextEncoding&);
+
 private:
     static const size_t kMaximumFragmentLengthTarget = 100;
 
@@ -115,6 +117,7 @@ private:
 
     String m_decodedURL;
     String m_decodedHTTPBody;
+    String m_httpBodyAsString;
     OwnPtr<SuffixTree<ASCIICodebook> > m_decodedHTTPBodySuffixTree;
 
     State m_state;