Support decoding opaque images to unpremul/premul

src/codec/SkJpegCodec.cpp

Index: src/codec/SkJpegCodec.cpp
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index e160f0c4e29a124aa09b03fcb6fd8dea37f57b0e..c2eee75c97a6d2280a676ccf8ef1dc76939c71ad 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -226,11 +226,6 @@ bool SkJpegCodec::setOutputColorSpace(const SkImageInfo& dst) {
         return false;
     }
 
-    // Ensure that the alpha type is opaque
-    if (kOpaque_SkAlphaType != dst.alphaType()) {
-        return false;
-    }
-
     // Check if we will decode to CMYK because a conversion to RGBA is not supported
     J_COLOR_SPACE colorSpace = fDecoderMgr->dinfo()->jpeg_color_space;
     bool isCMYK = JCS_CMYK == colorSpace || JCS_YCCK == colorSpace;