Don't do range adjustment in gfx::ColorTransform

Although gfx::ColorTransform can perform range adjustment (from limited
range to full range), it is not very accurate for high bit depths. Since
YUVAToRGBA() already performs range adjustment (using libavif
functions), set the range of the source color space to full range when
we create the gfx::ColorTransform object for YUV-to-RGB conversion.

Tested:
blink_platform_unittests --gtest_filter=*AVIF*

Bug: 960620
Change-Id: I74ff29ca0ca4199154477f24e65ad9f3496d5c93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2204819Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Wan-Teh Chang <wtc@google.com>
Cr-Commit-Position: refs/heads/master@{#769857}

third_party/blink/renderer/platform/image-decoders/avif/avif_image_decoder.cc

@@ -405,6 +405,7 @@ bool AVIFImageDecoder::DecodeImage(size_t index) {
 
 bool AVIFImageDecoder::UpdateColorTransform(const gfx::ColorSpace& src_cs,
                                             const gfx::ColorSpace& dest_cs) {
+  DCHECK_EQ(src_cs.GetRangeID(), gfx::ColorSpace::RangeID::FULL);
   if (color_transform_ && color_transform_->GetSrcColorSpace() == src_cs)
     return true;
   color_transform_ = gfx::ColorTransform::NewColorTransform(
@@ -422,6 +423,14 @@ bool AVIFImageDecoder::CanSetColorSpace() const {
 bool AVIFImageDecoder::RenderImage(const avifImage* image,
                                    const gfx::ColorSpace& frame_cs,
                                    ImageFrame* buffer) {
+  // Although gfx::ColorTransform can perform range adjustment (from limited
+  // range to full range), it uses the 8-bit equations for all bit depths, which
+  // are not very accurate for high bit depths. So YUVAToRGBA() performs range
+  // adjustment (using libavif) before calling gfx::ColorTransform::Transform().
+  // Therefore, the source color space passed to UpdateColorTransform() should
+  // be full range.
+  const gfx::ColorSpace frame_cs_full_range = frame_cs.GetWithMatrixAndRange(
+      frame_cs.GetMatrixID(), gfx::ColorSpace::RangeID::FULL);
   const gfx::ColorSpace dest_rgb_cs(*buffer->Bitmap().colorSpace());
 
   const bool is_mono = !image->yuvPlanes[AVIF_CHAN_U];
@@ -430,7 +439,7 @@ bool AVIFImageDecoder::RenderImage(const avifImage* image,
   // TODO(dalecurtis): We should decode to YUV when possible. Currently the
   // YUV path seems to only support still-image YUV8.
   if (decode_to_half_float_) {
-    if (!UpdateColorTransform(frame_cs, dest_rgb_cs)) {
+    if (!UpdateColorTransform(frame_cs_full_range, dest_rgb_cs)) {
       DVLOG(1) << "Failed to update color transform...";
       return false;
     }
@@ -503,7 +512,7 @@ bool AVIFImageDecoder::RenderImage(const avifImage* image,
     return true;
   }
 
-  if (!UpdateColorTransform(frame_cs, dest_rgb_cs)) {
+  if (!UpdateColorTransform(frame_cs_full_range, dest_rgb_cs)) {
     DVLOG(1) << "Failed to update color transform...";
     return false;
   }

third_party/blink/renderer/platform/image-decoders/avif/avif_image_decoder_test.cc

@@ -152,7 +152,7 @@ StaticColorCheckParam kTestParams[] = {
      ImageDecoder::kLosslessFormat,
      ImageDecoder::kAlphaNotPremultiplied,
      ColorBehavior::Tag(),
-     0,
+     1,
      {
          {gfx::Point(0, 0), SkColorSetARGB(255, 255, 0, 0)},
          {gfx::Point(1, 1), SkColorSetARGB(255, 255, 0, 0)},