Move all knowledge of X sampling into SkScaledCodec

src/codec/SkJpegCodec.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkJpegCodec_DEFINED
 #define SkJpegCodec_DEFINED
 
@@ skipping 40 matching lines @@
      */
     Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
             SkPMColor*, int*) override;
 
     SkEncodedFormat onGetEncodedFormat() const override {
         return kJPEG_SkEncodedFormat;
     }
 
     bool onRewind() override;
 
+    bool onDimensionsSupported(const SkISize&) override;
+
 private:
 
     /*
      * Read enough of the stream to initialize the SkJpegCodec.
      * Returns a bool representing success or failure.
      *
      * @param codecOut
      * If this returns true, and codecOut was not nullptr,
      * codecOut will be set to a new SkJpegCodec.
      *
@@ skipping 24 matching lines @@
 
     ~SkJpegCodec() override;
 
     /*
      * Checks if the conversion between the input image and the requested output
      * image has been implemented
      * Sets the output color space
      */
     bool setOutputColorSpace(const SkImageInfo& dst);
 
-    /*
-     * Checks if we can natively scale to the requested dimensions and natively scales the 
-     * dimensions if possible
-     */
-    bool nativelyScaleToDimensions(uint32_t width, uint32_t height); 
-
     // scanline decoding
-    Result initializeSwizzler(const SkImageInfo&, const SkCodec::Options&);
+    SkSampler* getSampler() override;
     Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options,
                    SkPMColor ctable[], int* ctableCount) override;
     Result onGetScanlines(void* dst, int count, size_t rowBytes) override;
     Result onSkipScanlines(int count) override;
 
     SkAutoTDelete<JpegDecoderMgr> fDecoderMgr;
     // We will save the state of the decompress struct after reading the header.
     // This allows us to safely call onGetScaledDimensions() at any time.
     const int                     fReadyState;
 
     // scanline decoding
     SkAutoMalloc               fStorage;    // Only used if sampling is needed
     uint8_t*                   fSrcRow;     // Only used if sampling is needed
     SkAutoTDelete<SkSwizzler>  fSwizzler;
     
     typedef SkCodec INHERITED;
 };
 
 #endif