Remove DocumentParser::flush which is not used by anyone.

third_party/WebKit/Source/core/dom/DecodedDataDocumentParser.h

 /*
  * 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 @@
 class TextResourceDecoder;
 
 class DecodedDataDocumentParser : public DocumentParser {
 public:
     // Only used by the XMLDocumentParser to communicate back to
     // XMLHttpRequest if the responseXML was well formed.
     virtual bool wellFormed() const { return true; }
 
     // The below functions are used by DocumentWriter (the loader).
     void appendBytes(const char* bytes, size_t length) override;
-    void flush() override;
+    virtual void flush();
     bool needsDecoder() const final { return m_needsDecoder; }
     void setDecoder(PassOwnPtr<TextResourceDecoder>) override;
     TextResourceDecoder* decoder() final;
 
     PassOwnPtr<TextResourceDecoder> takeDecoder();
 
 protected:
     explicit DecodedDataDocumentParser(Document&);
     ~DecodedDataDocumentParser() override;
 
 private:
     void updateDocument(String& decodedData);
 
     bool m_needsDecoder;
     OwnPtr<TextResourceDecoder> m_decoder;
 };
 
 }
 
 #endif // DecodedDataDocumentParser_h