BMP-in-ICO should respect alpha in Windows V3 32bpp RGB bitmaps.

Source/platform/image-decoders/bmp/BMPImageReader.h

 /*
  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 50 matching lines @@
     #if CPU(BIG_ENDIAN)
         result = ((result & 0xff) << 24) | ((result & 0xff00) << 8) | ((result & 0xff0000) >> 8) | ((result & 0xff000000) >> 24);
     #endif
         return result;
     }
 
     // |parent| is the decoder that owns us.
     // |startOffset| points to the start of the BMP within the file.
     // |buffer| points at an empty ImageFrame that we'll initialize and
     // fill with decoded data.
-    BMPImageReader(ImageDecoder* parent, size_t decodedAndHeaderOffset, size_t imgDataOffset, bool usesAndMask);
+    BMPImageReader(ImageDecoder* parent, size_t decodedAndHeaderOffset, size_t imgDataOffset, bool m_isInICO);

[Stephen White, 2014/05/07 22:38:55]

Spurious m_.

[Peter Kasting, 2014/05/07 22:41:29]

Darn!  Good catch.  Will fix.

 
     void setBuffer(ImageFrame* buffer) { m_buffer = buffer; }
     void setData(SharedBuffer* data) { m_data = data; }
 
     // Does the actual decoding.  If |onlySize| is true, decoding only
     // progresses as far as necessary to get the image size.  Returns
     // whether decoding succeeded.
     bool decodeBMP(bool onlySize);
 
 private:
     // The various BMP compression types.  We don't currently decode all
     // these.
     enum CompressionType {
         // Universal types
         RGB = 0,
         RLE8 = 1,
         RLE4 = 2,
         // Windows V3+ only
         BITFIELDS = 3,
         JPEG = 4,
         PNG = 5,
         // OS/2 2.x-only
         HUFFMAN1D,  // Stored in file as 3
         RLE24,      // Stored in file as 4
     };
-    enum AndMaskState {
-        None,
-        NotYetDecoded,
-        Decoding,
-    };
     enum ProcessingResult {
         Success,
         Failure,
         InsufficientData,
     };
 
     // These are based on the Windows BITMAPINFOHEADER and RGBTRIPLE
     // structs, but with unnecessary entries removed.
     struct BitmapInfoHeader {
         uint32_t biSize;
@@ skipping 224 matching lines @@
 
     // The coordinate to which we've decoded the image.
     IntPoint m_coord;
 
     // Variables that track whether we've seen pixels with alpha values != 0
     // and == 0, respectively.  See comments in processNonRLEData() on how
     // these are used.
     bool m_seenNonZeroAlphaPixel;
     bool m_seenZeroAlphaPixel;
 
+    // BMPs-in-ICOs have a few differences from standalone BMPs, so we need to
+    // know if we're in an ICO container.
+    bool m_isInICO;
+
     // ICOs store a 1bpp "mask" immediately after the main bitmap image data
     // (and, confusingly, add its height to the biHeight value in the info
-    // header, thus doubling it).  This variable tracks whether we have such
-    // a mask and if we've started decoding it yet.
-    AndMaskState m_andMaskState;
+    // header, thus doubling it). If |m_isInICO| is true, this variable tracks
+    // whether we've begun decoding this mask yet.
+    bool m_decodingAndMask;
 };
 
 } // namespace WebCore
 
 #endif