Scanline decoding for wbmp

src/codec/SkCodec_wbmp.h

Index: src/codec/SkCodec_wbmp.h
diff --git a/src/codec/SkCodec_wbmp.h b/src/codec/SkCodec_wbmp.h
index fece249728e72e1f2d0fcd0700981a84a116a8da..0db9380fef30fe55075679c6f32012c229d54778 100644
--- a/src/codec/SkCodec_wbmp.h
+++ b/src/codec/SkCodec_wbmp.h
@@ -9,6 +9,8 @@
 #define SkCodec_wbmp_DEFINED
 
 #include "SkCodec.h"
+#include "SkScanlineDecoder.h"
+#include "SkSwizzler.h"
 
 class SkWbmpCodec final : public SkCodec {
 public:
@@ -18,8 +20,17 @@ protected:
     SkEncodedFormat onGetEncodedFormat() const override;
     Result onGetPixels(const SkImageInfo&, void*, size_t,
                        const Options&, SkPMColor[], int*) override;
+    SkScanlineDecoder* onGetScanlineDecoder(const SkImageInfo& dstInfo,
+            const Options& options, SkPMColor ctable[], int* ctableCount) override;
 private:
+    /*
+     * Returns a swizzler on success, NULL on failure
+     */
+    SkSwizzler* initializeSwizzler(const SkImageInfo& info, const SkPMColor* ctable,
+                                   const Options& opts);
     SkWbmpCodec(const SkImageInfo&, SkStream*);
+
+    friend class SkWbmpScanlineDecoder;
     typedef SkCodec INHERITED;
 };