SkPDF/Deflate: clean up old SkFlate code

src/core/SkStreamPriv.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkStreamPriv_DEFINED
 #define SkStreamPriv_DEFINED
 
@@ skipping 25 matching lines @@
 SkData *SkCopyStreamToData(SkStream* stream);
 
 /**
  *  Attempt to convert this stream to a StreamRewindable in the
  *  cheapest possible manner (calling duplicate() if possible, and
  *  otherwise allocating memory for a copy).  The position of the
  *  input stream is left in an indeterminate state.
  */
 SkStreamRewindable* SkStreamRewindableFromSkStream(SkStream* stream);
 
+/**
+ *  Copies the input stream from the current position to the end.
+ *  Does not rewind the input stream.
+ */
+bool SkStreamCopy(SkWStream* out, SkStream* input);
+
 #endif  // SkStreamPriv_DEFINED