Scanline decoding for bmp

src/codec/SkBmpMaskCodec.cpp

Index: src/codec/SkBmpMaskCodec.cpp
diff --git a/src/codec/SkBmpMaskCodec.cpp b/src/codec/SkBmpMaskCodec.cpp
index 1c89ba1c84de158d80efa8725aebeef6d6b6c68c..22813e606a5beb67546f8c11fb6a8518a87c5b90 100644
--- a/src/codec/SkBmpMaskCodec.cpp
+++ b/src/codec/SkBmpMaskCodec.cpp
@@ -108,3 +108,14 @@ SkCodec::Result SkBmpMaskCodec::decode(const SkImageInfo& dstInfo,
     // Finished decoding the entire image
     return kSuccess;
 }
+
+SkCodec::Result SkBmpMaskCodec::onStart(const SkImageInfo& dstInfo,
+        const SkCodec::Options& options, SkPMColor inputColorPtr[], int* inputColorCount) {
+    // Initialize a the mask swizzler
+    if (!this->initializeSwizzler(dstInfo)) {
+        SkCodecPrintf("Error: cannot initialize swizzler.\n");
+        return SkCodec::kInvalidConversion;
+    }
+
+    return SkCodec::kSuccess;
+}