Move all knowledge of X sampling into SkScaledCodec

src/codec/SkCodec_libico.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.
  */
 
 #include "SkCodec.h"
 #include "SkImageInfo.h"
 #include "SkStream.h"
@@ skipping 17 matching lines @@
      */
     static SkCodec* NewFromStream(SkStream*);
 
 protected:
 
     /*
      * Chooses the best dimensions given the desired scale
      */
     SkISize onGetScaledDimensions(float desiredScale) const override;
 
+    bool onDimensionsSupported(const SkISize&) override;
+
     /*
      * Initiates the Ico decode
      */
     Result onGetPixels(const SkImageInfo& dstInfo, void* dst,
                        size_t dstRowBytes, const Options&, SkPMColor*, int*)
                        override;
 
     SkEncodedFormat onGetEncodedFormat() const override {
         return kICO_SkEncodedFormat;
     }
 
 private:
 
     /*
      * Constructor called by NewFromStream
      * @param embeddedCodecs codecs for the embedded images, takes ownership
      */
     SkIcoCodec(const SkImageInfo& srcInfo,
                SkTArray<SkAutoTDelete<SkCodec>, true>* embeddedCodecs);
 
     SkAutoTDelete<SkTArray<SkAutoTDelete<SkCodec>, true>>
             fEmbeddedCodecs; // owned
 
     typedef SkCodec INHERITED;
 };