Bug 2069212. Regenerate the JXL gtest reference so we can ask for an exact match. r=saschanaz

large-jxl-reference.webp held libjxl's decode of large.jxl. jxl-rs changed its
dither pattern again in
https://github.com/libjxl/jxl-rs/commit/b76fd1421ed675bd35a4996fecafc124bf47f75e
and now it is different from libjxl (it used to match). I want this test case
in particular to be an exact match (or as close as we can get) so I regenerated
it from jxl-rs. webp was used because I wanted a different format decoder to
check against and because this is a big file (necessary for testing
multithreaded decoding) and webp produced the smallest lossless file from a
decoder that wasn't jxl.

Differential Revision: https://phabricator.services.mozilla.com/D325239

image/test/gtest/Common.cpp

@@ -1057,8 +1057,11 @@ ImageTestCase LargeJXLTestCase() {
                        TEST_CASE_IGNORE_OUTPUT);
 }
 
-// The pixels of large.jxl, as libjxl decodes them, in a lossless format some
-// other decoder can read back exactly.
+// The pixels of large.jxl, as a known good jxl-rs decodes them, in a lossless
+// format some other decoder can read back exactly. Matches libjxl's decode to
+// within 1 per channel, the two dithering 8-bit output differently. Regenerate
+// with `jxl_cli --data-type u8 large.jxl ref.png` and `cwebp -z 9 ref.png -o
+// large-jxl-reference.webp`.
 ImageTestCase LargeJXLReferenceWebPTestCase() {
   return ImageTestCase("large-jxl-reference.webp", "image/webp",
                        IntSize(1200, 660), TEST_CASE_IGNORE_OUTPUT);

image/test/gtest/TestDecoders.cpp

@@ -1181,8 +1181,16 @@ TEST_F(ImageDecoders, JXLParallelDecodeMatchesSerial) {
   {
     // Compare to the same image in another format to make sure it's the right
     // reference.
-    const uint32_t kLibjxlMaxDifferingPixels = 18;
-    const uint8_t kLibjxlMaxChannelDiff = 1;
+#if defined(XP_WIN) && !defined(HAVE_64BIT_BUILD)
+    const uint32_t kReferenceMaxDifferingPixels = 7;
+    const uint8_t kReferenceMaxChannelDiff = 1;
+#elif defined(ANDROID)
+    const uint32_t kReferenceMaxDifferingPixels = 4;
+    const uint8_t kReferenceMaxChannelDiff = 1;
+#else
+    const uint32_t kReferenceMaxDifferingPixels = 0;
+    const uint8_t kReferenceMaxChannelDiff = 0;
+#endif
     ImageTestCase referenceCase = LargeJXLReferenceWebPTestCase();
     RefPtr<SourceSurface> webpReference;
     WithSingleChunkDecode(referenceCase, Nothing(), /* aUseDecodePool */ false,
@@ -1190,8 +1198,9 @@ TEST_F(ImageDecoders, JXLParallelDecodeMatchesSerial) {
                             webpReference =
                                 CheckDecoderState(referenceCase, aDecoder);
                           });
-    ExpectSurfacesSimilar(webpReference, reference, kLibjxlMaxDifferingPixels,
-                          kLibjxlMaxChannelDiff);
+    ExpectSurfacesSimilar(webpReference, reference,
+                          kReferenceMaxDifferingPixels,
+                          kReferenceMaxChannelDiff);
   }
 
   for (bool useDecodePool : {false, true}) {