Include transform origin in the transform tree.

Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp

Index: Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp
diff --git a/Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp b/Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp
index 0db60777835416257bfa8e089e2b6c2930c3c6c5..a1f76c70f36cecc81bf5029427f78f8d95d45ad0 100644
--- a/Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp
+++ b/Source/platform/graphics/paint/DisplayItemPropertyTreeBuilderTest.cpp
@@ -415,5 +415,28 @@ TEST_F(DisplayItemPropertyTreeBuilderTest, ScrollDisplayItemIs2DTranslation)
         AllOf(hasRange(4, 5), hasTransformNode(0), hasOffset(FloatSize(0, 0)))));
 }
 
+TEST_F(DisplayItemPropertyTreeBuilderTest, TransformTreeIncludesTransformOrigin)
+{
+    FloatPoint3D transformOrigin(1, 2, 3);
+    TransformationMatrix matrix;
+    matrix.scale3d(2, 2, 2);
+
+    auto transformClient = processBeginTransform3D(matrix, transformOrigin);
+    processDummyDisplayItem();
+    processEndTransform3D(transformClient);
+    finishPropertyTrees();
+
+    // There should be two transform nodes.
+    ASSERT_EQ(2u, transformTree().nodeCount());
+    EXPECT_TRUE(transformTree().nodeAt(0).isRoot());
+
+    // And the non-root node should have both the matrix and the origin,
+    // separately.
+    const auto& transformNode = transformTree().nodeAt(1);
+    EXPECT_EQ(0u, transformNode.parentNodeIndex);
+    EXPECT_EQ(TransformationMatrix::toSkMatrix44(matrix), transformNode.matrix);
+    EXPECT_EQ(transformOrigin, transformNode.transformOrigin);
+}
+
 } // namespace
 } // namespace blink