Make image decoders faster by refactoring hot loops that fills the lines of ImageFrame.

Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp

Index: Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp
diff --git a/Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp b/Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp
index 7974b79a7ee2dd3a4fbb4c7579bab8dad2315872..4251d946b4339d5112f87b8ead56785ac1d9d580 100644
--- a/Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp
+++ b/Source/core/platform/image-decoders/jpeg/JPEGImageDecoder.cpp
@@ -646,17 +646,7 @@ template <J_COLOR_SPACE colorSpace> void setPixel(ImageFrame& buffer, ImageFrame
         buffer.setRGBA(pixel, jsample[0], jsample[1], jsample[2], 0xFF);
         break;
     case JCS_CMYK:
-        // Source is 'Inverted CMYK', output is RGB.
-        // See: http://www.easyrgb.com/math.php?MATH=M12#text12
-        // Or: http://www.ilkeratalay.com/colorspacesfaq.php#rgb
-        // From CMYK to CMY:
-        // X =   X    * (1 -   K   ) +   K  [for X = C, M, or Y]
-        // Thus, from Inverted CMYK to CMY is:
-        // X = (1-iX) * (1 - (1-iK)) + (1-iK) => 1 - iX*iK
-        // From CMY (0..1) to RGB (0..1):
-        // R = 1 - C => 1 - (1 - iC*iK) => iC*iK  [G and B similar]
-        unsigned k = jsample[3];
-        buffer.setRGBA(pixel, jsample[0] * k / 255, jsample[1] * k / 255, jsample[2] * k / 255, 0xFF);
+        buffer.setInvertedCMYK(pixel, jsample[0], jsample[1], jsample[2], jsample[3]);
         break;
     }
 }