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..efbc4c6a3c676d310742967693c9715819f84076 100644
--- a/src/codec/SkBmpMaskCodec.h
+++ b/src/codec/SkBmpMaskCodec.h
@@ -29,7 +29,8 @@ 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);
+            SkBmpCodec::BmpInputFormat inputFormat, uint16_t bitsPerPixel,
+            SkMasks* masks, RowOrder rowOrder);
 
 protected:
 
@@ -48,5 +49,30 @@ private:
     SkAutoTDelete<SkMaskSwizzler>       fMaskSwizzler;
     SkAutoTDeleteArray<uint8_t>         fSrcBuffer;
 
+    friend class SkBmpMaskScanlineDecoder;
+
     typedef SkBmpCodec INHERITED;
 };
+
+/*
+ * Scanline decoder for mask bmps
+ */
+class SkBmpMaskScanlineDecoder : public SkScanlineDecoder {
+public:
+    SkBmpMaskScanlineDecoder(SkBmpMaskCodec* codec);
+
+    SkCodec::Result onStart(const SkImageInfo& dstInfo, const SkCodec::Options& options,
+                            SkPMColor inputColorPtr[], int* inputColorCount) override;
+
+    SkCodec::Result onGetScanlines(void* dst, int count, size_t rowBytes) override;
+
+    // TODO(msarett): Override default skipping with something more clever.
+    // TODO(msarett): Consider other optimizations for this codec.
+
+private:
+    SkAutoTDelete<SkBmpMaskCodec>     fCodec;
+    SkImageInfo                       fDstInfo;
+    SkCodec::Options                  fOpts;
+
+    typedef SkScanlineDecoder INHERITED;
+};