Add support for flattening in GeometryMapper.

third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp

Index: third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp b/third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp
index 7c44f7b1c2c3b125fd45a24665f38b68954e5cba..cdda820d20f10f760b776f9342acf6da1008d112 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/GeometryMapperTest.cpp
@@ -276,6 +276,32 @@ TEST_F(GeometryMapperTest, NestedTransforms) {
       *getTransform(transform1.get(), rootPropertyTreeState().transform()));
 }
 
+TEST_F(GeometryMapperTest, NestedTransformsFlattening) {
+  TransformationMatrix rotateTransform;
+  rotateTransform.rotate3d(45, 0, 0);
+  RefPtr<TransformPaintPropertyNode> transform1 =
+      TransformPaintPropertyNode::create(rootPropertyTreeState().transform(),
+                                         rotateTransform, FloatPoint3D());
+
+  TransformationMatrix inverseRotateTransform;
+  inverseRotateTransform.rotate3d(-45, 0, 0);
+  RefPtr<TransformPaintPropertyNode> transform2 =
+      TransformPaintPropertyNode::create(transform1, inverseRotateTransform,
+                                         FloatPoint3D(),
+                                         true);  // Flattens
+
+  PropertyTreeState localState = rootPropertyTreeState();
+  localState.setTransform(transform2.get());
+
+  FloatRect input(0, 0, 100, 100);
+  rotateTransform.flattenTo2d();
+  TransformationMatrix final = rotateTransform * inverseRotateTransform;
+  FloatRect output = final.mapRect(input);
+  bool hasRadius = false;
+  CHECK_MAPPINGS(input, output, output, final, FloatClipRect(), localState,
+                 rootPropertyTreeState(), hasRadius);
+}
+
 TEST_F(GeometryMapperTest, NestedTransformsScaleAndTranslation) {
   TransformationMatrix scaleTransform;
   scaleTransform.scale(2);
@@ -819,11 +845,11 @@ TEST_F(GeometryMapperTest, FilterWithClipsAndTransforms) {
   EXPECT_EQ(FloatRect(-150, -150, 450, 450), output);
 
   bool hasRadius = false;
-  CHECK_MAPPINGS(
-      input, output, FloatRect(0, 0, 300, 300),
-      transformAboveEffect->matrix() * transformBelowEffect->matrix(),
-      FloatClipRect(FloatRect(30, 30, 270, 270)), localState,
-      rootPropertyTreeState(), hasRadius);
+  TransformationMatrix combinedTransform =
+      transformAboveEffect->matrix() * transformBelowEffect->matrix();
+  CHECK_MAPPINGS(input, output, FloatRect(0, 0, 300, 300), combinedTransform,
+                 FloatClipRect(FloatRect(30, 30, 270, 270)), localState,
+                 rootPropertyTreeState(), hasRadius);
 }
 
 TEST_F(GeometryMapperTest, ReflectionWithPaintOffset) {