Revert of Do not consolidate data in BMPImageDecoder

Source/platform/image-decoders/FastSharedBufferReader.h

 /*
  * Copyright (C) 2015 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 28 matching lines @@
 namespace blink {
 
 // This class is used by image decoders to avoid memory consolidation and
 // therefore minimizes the cost of memory copying when the decoders
 // repeatedly read from a buffer that is continually growing due to network
 // traffic.
 class PLATFORM_EXPORT FastSharedBufferReader {
 public:
     FastSharedBufferReader(PassRefPtr<SharedBuffer> data);
 
-    void setData(PassRefPtr<SharedBuffer>);
-
     // Returns a consecutive buffer that carries the data starting
     // at |dataPosition| with |length| bytes.
     // This method returns a pointer to a memory segment stored in
     // |m_data| if such a consecutive buffer can be found.
     // Otherwise copies into |buffer| and returns it.
     // Caller must ensure there are enough bytes in |m_data| and |buffer|.
     const char* getConsecutiveData(size_t dataPosition, size_t length, char* buffer) const;
 
     // Wraps SharedBuffer::getSomeData().
     size_t getSomeData(const char*& someData, size_t dataPosition) const;
@@ skipping 20 matching lines @@
     mutable const char* m_segment;
     mutable size_t m_segmentLength;
 
     // Data position in |m_data| pointed to by |m_segment|.
     mutable size_t m_dataPosition;
 };
 
 } // namespace blink
 
 #endif