Consolidate SkCodec functions for handling rewind

src/codec/SkBmpStandardCodec.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 "SkBmpCodec.h"
 #include "SkColorTable.h"
 #include "SkImageInfo.h"
@@ skipping 27 matching lines @@
     SkBmpStandardCodec(const SkImageInfo& srcInfo, SkStream* stream,
                uint16_t bitsPerPixel, uint32_t numColors, uint32_t bytesPerColor,
                uint32_t offset, SkBmpCodec::RowOrder rowOrder, bool isIco);
 
 protected:
 
     Result onGetPixels(const SkImageInfo& dstInfo, void* dst,
                        size_t dstRowBytes, const Options&, SkPMColor*,
                        int*) override;
 
+    bool onInIco() const override {
+        return fInIco;
+    }
 private:
 
     /*
      * Creates the color table
      * Sets colorCount to the new color count if it is non-NULL
      */
     bool createColorTable(SkAlphaType alphaType, int* colorCount);
 
     bool initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts);
 
     Result decode(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options& opts);
 
     SkAutoTUnref<SkColorTable>          fColorTable;     // owned
     const uint32_t                      fNumColors;
     const uint32_t                      fBytesPerColor;
     const uint32_t                      fOffset;
     SkAutoTDelete<SkSwizzler>           fSwizzler;
     SkAutoTDeleteArray<uint8_t>         fSrcBuffer;
     const bool                          fInIco;
 
     typedef SkBmpCodec INHERITED;
 };