Scanline decoding for bmp

src/codec/SkBmpMaskCodec.h

Index: src/codec/SkBmpMaskCodec.h
diff --git a/src/codec/SkBmpMaskCodec.h b/src/codec/SkBmpMaskCodec.h
index 6f43bb3f85ce23424892f05557fda750ebdda77e..8b5a87ca7fe5b051b35761d67b665c73598332bd 100644
--- a/src/codec/SkBmpMaskCodec.h
+++ b/src/codec/SkBmpMaskCodec.h
@@ -29,7 +29,7 @@ public:
      * @param rowOrder indicates whether rows are ordered top-down or bottom-up
      */
     SkBmpMaskCodec(const SkImageInfo& srcInfo, SkStream* stream,
-                   uint16_t bitsPerPixel, SkMasks* masks, RowOrder rowOrder);
+            uint16_t bitsPerPixel, SkMasks* masks, RowOrder rowOrder);
 
 protected:
 
@@ -41,8 +41,12 @@ private:
 
     bool initializeSwizzler(const SkImageInfo& dstInfo);
 
+    SkCodec::Result prepareToDecode(const SkImageInfo& dstInfo,
+            const SkCodec::Options& options, SkPMColor inputColorPtr[],
+            int* inputColorCount) override;
+
     Result decode(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes,
-                  const Options& opts);
+                  const Options& opts) override;
 
     SkAutoTDelete<SkMasks>              fMasks;        // owned
     SkAutoTDelete<SkMaskSwizzler>       fMaskSwizzler;