Fix border radius on composited children.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp
index b5087ac67a04668b91bed6601e7e977b96697c71..f20e8160fbf2881374367e680c24213c6652d88f 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMappingTest.cpp
@@ -1084,4 +1084,85 @@ TEST_P(CompositedLayerMappingTest, RootScrollerAncestorsNotClipped) {
   }
 }
 
+TEST_P(CompositedLayerMappingTest, AncestorClippingMaskLayerUpdates) {
+  setBodyInnerHTML(
+      "<style>"
+      "#ancestor { width: 100px; height: 100px; overflow: hidden; }"
+      "#child { width: 120px; height: 120px; background-color: green; }"
+      "</style>"
+      "<div id='ancestor'><div id='child'></div></div>");
+  document().view()->updateAllLifecyclePhases();
+
+  Element* ancestor = document().getElementById("ancestor");
+  ASSERT_TRUE(ancestor);
+  PaintLayer* ancestorPaintLayer =
+      toLayoutBoxModelObject(ancestor->layoutObject())->layer();
+  ASSERT_TRUE(ancestorPaintLayer);
+
+  CompositedLayerMapping* ancestorMapping =
+      ancestorPaintLayer->compositedLayerMapping();
+  ASSERT_FALSE(ancestorMapping);
+
+  Element* child = document().getElementById("child");
+  ASSERT_TRUE(child);
+  PaintLayer* childPaintLayer =
+      toLayoutBoxModelObject(child->layoutObject())->layer();
+  ASSERT_FALSE(childPaintLayer);
+
+  // Making the child conposited causes creation of an AncestorClippingLayer.
+  child->setAttribute(HTMLNames::styleAttr, "will-change: transform");
+  document().view()->updateAllLifecyclePhases();
+
+  childPaintLayer = toLayoutBoxModelObject(child->layoutObject())->layer();
+  ASSERT_TRUE(childPaintLayer);
+  CompositedLayerMapping* childMapping =
+      childPaintLayer->compositedLayerMapping();
+  ASSERT_TRUE(childMapping);
+  EXPECT_TRUE(childMapping->ancestorClippingLayer());
+  EXPECT_FALSE(childMapping->ancestorClippingLayer()->maskLayer());
+  EXPECT_FALSE(childMapping->ancestorClippingMaskLayer());
+
+  // Adding border radius to the ancestor requires an
+  // ancestorClippingMaskLayer for the child
+  ancestor->setAttribute(HTMLNames::styleAttr, "border-radius: 40px;");
+  document().view()->updateAllLifecyclePhases();
+
+  childPaintLayer = toLayoutBoxModelObject(child->layoutObject())->layer();
+  ASSERT_TRUE(childPaintLayer);
+  childMapping = childPaintLayer->compositedLayerMapping();
+  ASSERT_TRUE(childMapping);
+  EXPECT_TRUE(childMapping->ancestorClippingLayer());
+  EXPECT_TRUE(childMapping->ancestorClippingLayer()->maskLayer());
+  EXPECT_TRUE(childMapping->ancestorClippingMaskLayer());
+
+  // Removing the border radius should remove the ancestorClippingMaskLayer
+  // for the child
+  ancestor->setAttribute(HTMLNames::styleAttr, "border-radius: 0px;");
+  document().view()->updateAllLifecyclePhases();
+
+  childPaintLayer = toLayoutBoxModelObject(child->layoutObject())->layer();
+  ASSERT_TRUE(childPaintLayer);
+  childMapping = childPaintLayer->compositedLayerMapping();
+  ASSERT_TRUE(childMapping);
+  EXPECT_TRUE(childMapping->ancestorClippingLayer());
+  EXPECT_FALSE(childMapping->ancestorClippingLayer()->maskLayer());
+  EXPECT_FALSE(childMapping->ancestorClippingMaskLayer());
+
+  // Add border radius back so we can test one more case
+  ancestor->setAttribute(HTMLNames::styleAttr, "border-radius: 40px;");
+  document().view()->updateAllLifecyclePhases();
+
+  // Now change the overflow to remove the need for an ancestor clip
+  // on the child
+  ancestor->setAttribute(HTMLNames::styleAttr, "overflow: visible");
+  document().view()->updateAllLifecyclePhases();
+
+  childPaintLayer = toLayoutBoxModelObject(child->layoutObject())->layer();
+  ASSERT_TRUE(childPaintLayer);
+  childMapping = childPaintLayer->compositedLayerMapping();
+  ASSERT_TRUE(childMapping);
+  EXPECT_FALSE(childMapping->ancestorClippingLayer());
+  EXPECT_FALSE(childMapping->ancestorClippingMaskLayer());
+}
+
 }  // namespace blink