Ensure SVG PaintOffset is reset at the HTML/SVG boundary [spv2]

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilderTest.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutTreeAsText.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "platform/graphics/paint/GeometryMapper.h"
 #include "platform/graphics/paint/TransformPaintPropertyNode.h"
@@ skipping 1068 matching lines @@
     ObjectPaintProperties* fixedProperties = document().getElementById("fixed")->layoutObject()->objectPaintProperties();
     // The residual subpixel adjustment should still be (-0.3,0).
     EXPECT_EQ(subpixelAccumulation, fixedProperties->localBorderBoxProperties()->paintOffset);
 
     // d should be painted starting at subpixelAccumulation + (0.7,0) = (0.4,0).
     LayoutPoint dPaintOffset = subpixelAccumulation + LayoutPoint(FloatPoint(0.7, 0));
     ObjectPaintProperties* dProperties = document().getElementById("d")->layoutObject()->objectPaintProperties();
     EXPECT_EQ(dPaintOffset, dProperties->localBorderBoxProperties()->paintOffset);
 }
 
+TEST_F(PaintPropertyTreeBuilderTest, SvgPixelSnappingShouldResetPaintOffset)
+{
+    setBodyInnerHTML(
+        "<svg id='svg' style='position: relative; left: 0.1px; transform: matrix(1, 0, 0, 1, 0, 0);'>"
+        "    <rect id='rect' transform='translate(1, 1)'/>"
+        "</svg>");
+
+    LayoutObject& svgWithTransform = *document().getElementById("svg")->layoutObject();
+    ObjectPaintProperties* svgWithTransformProperties = svgWithTransform.objectPaintProperties();
+    EXPECT_EQ(TransformationMatrix(), svgWithTransformProperties->transform()->matrix());
+    EXPECT_EQ(LayoutPoint(FloatPoint(0.1, 0)), svgWithTransformProperties->localBorderBoxProperties()->paintOffset);
+    EXPECT_EQ(nullptr, svgWithTransformProperties->svgLocalToBorderBoxTransform());
+
+    LayoutObject& rectWithTransform = *document().getElementById("rect")->layoutObject();
+    ObjectPaintProperties* rectWithTransformProperties = rectWithTransform.objectPaintProperties();
+    EXPECT_EQ(TransformationMatrix().translate(1, 1), rectWithTransformProperties->transform()->matrix());
+
+    // Ensure there is no PaintOffset transform between the rect and the svg's transform.
+    EXPECT_EQ(svgWithTransformProperties->transform(), rectWithTransformProperties->transform()->parent());
+}
+
 } // namespace blink