ColorFilterLayer clips to its paint bounds

flow/layers/color_filter_layer.cc

@@ -82,6 +82,16 @@ void ColorFilterLayer::Paint(PaintContext& context) const {
     }
   }
 
+  // If the color filter modifies transparent black, then when it's applied to
+  // a saveLayer, that layer will extend beyond the paint bounds provided in the
+  // SaveLayerRec (which defines the bounds of the content within the layer, not
+  // the extent of the layer during the restore()). ColorFilterLayer must clip
+  // before the saveLayer in these cases to ensure it doesn't go beyond its
+  // reported paint_bounds().
+  if (filter_ && filter_->modifies_transparent_black()) {
+    mutator.clipRect(paint_bounds(), /*is_aa=*/false);
+  }
+
   // Now apply the color filter and then try rendering children either from
   // cache or directly.
   mutator.applyColorFilter(paint_bounds(), filter_);

flow/layers/color_filter_layer_unittests.cc

@@ -447,5 +447,48 @@ TEST_F(ColorFilterLayerTest, OpacityInheritance) {
   EXPECT_TRUE(DisplayListsEQ_Verbose(expected_builder.Build(), display_list()));
 }
 
+TEST_F(ColorFilterLayerTest, ModifiesTransparentBlack) {
+  // In Skia, saveLayers with a color filter that modifies transparent black
+  // will fill all pixels within the clip, going beyond the user bounds hint.
+  // ColorFilterLayer must insert a clipRect before saveLayer to ensure it
+  // doesn't draw beyond its reported bounds.
+  // clang-format off
+  float matrix[20] = {
+    -1, 0, 0, 0, 1,
+     0,-1, 0, 0, 1,
+     0, 0,-1, 0, 1,
+     0, 0, 0,-1, 1,
+  };
+  // clang-format on
+  auto layer_filter = DlMatrixColorFilter(matrix);
+  ASSERT_TRUE(layer_filter.modifies_transparent_black());
+
+  const SkPath child_path = SkPath().addRect(SkRect::MakeWH(5.0f, 5.0f));
+  auto mock_layer = std::make_shared<MockLayer>(child_path);
+  auto color_filter_layer = std::make_shared<ColorFilterLayer>(
+      std::make_shared<DlMatrixColorFilter>(matrix));
+  color_filter_layer->Add(mock_layer);
+
+  color_filter_layer->Preroll(preroll_context());
+
+  DisplayListBuilder expected_builder;
+  /* ColorFilterLayer::Paint() */ {
+    DlPaint dl_paint;
+    dl_paint.setColorFilter(&layer_filter);
+    expected_builder.Save();
+    expected_builder.ClipRect(child_path.getBounds(),
+                              DlCanvas::ClipOp::kIntersect, /*is_aa=*/false);
+    expected_builder.SaveLayer(&child_path.getBounds(), &dl_paint);
+    /* MockLayer::Paint() */ {
+      expected_builder.DrawPath(child_path, DlPaint(0xFF000000));
+    }
+    expected_builder.Restore();
+    expected_builder.Restore();
+  }
+
+  color_filter_layer->Paint(display_list_paint_context());
+  EXPECT_TRUE(DisplayListsEQ_Verbose(expected_builder.Build(), display_list()));
+}
+
 }  // namespace testing
 }  // namespace flutter

tools/gn

@@ -300,8 +300,6 @@ def to_gn_args(args):
   gn_args['skia_use_wuffs'] = True
   gn_args['skia_use_expat'] = args.target_os == 'android'
   gn_args['skia_use_fontconfig'] = args.enable_fontconfig
-  gn_args['skia_use_legacy_layer_bounds'
-         ] = True  # Temporary: See skbug.com/12083, skbug.com/12303.
   gn_args['skia_use_legacy_colorfilter_imagefilter'] = True  # Temporary staging
   gn_args['skia_use_icu'] = True
   gn_args['is_official_build'] = True  # Disable Skia test utilities.