SkPDF: add `final` keyword to leaf classes

src/pdf/SkDeflate.h

 
 /*
  * Copyright 2010 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkFlate_DEFINED
 #define SkFlate_DEFINED
 
 #include "SkTypes.h"
 
 #include "SkStream.h"
 
 /**
   * Wrap a stream in this class to compress the information written to
   * this stream using the Deflate algorithm.  Uses Zlib's
   * Z_DEFAULT_COMPRESSION level.
   *
   * See http://en.wikipedia.org/wiki/DEFLATE
   */
-class SkDeflateWStream : public SkWStream {
+class SkDeflateWStream final : public SkWStream {
 public:
     /** Does not take ownership of the stream. */
     SkDeflateWStream(SkWStream*);
 
     /** The destructor calls finalize(). */
     ~SkDeflateWStream();
 
     /** Write the end of the compressed stream.  All subsequent calls to
         write() will fail. Subsequent calls to finalize() do nothing. */
     void finalize();
 
     // The SkWStream interface:
     bool write(const void*, size_t) override;
     size_t bytesWritten() const override;
 
 private:
     struct Impl;
     SkAutoTDelete<Impl> fImpl;
 };
 
 #endif  // SkFlate_DEFINED