Reland of Don't traverse non-stacked layer under composited child in traverseNonCompositingDescendants

third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp b/third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp
index 6a86f8c51280fd286c050447144efd31bf19439b..1a1b566159e7be87fc9a628b32461838221ea1b1 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObjectTest.cpp
@@ -4,9 +4,11 @@
 
 #include "core/layout/LayoutObject.h"
 
+#include "core/frame/FrameView.h"
 #include "core/layout/LayoutTestHelper.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutAPIShim.h"
+#include "platform/JSONValues.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
@@ -124,4 +126,43 @@ TEST_F(LayoutObjectTest, PaintingLayerOfOverflowClipLayerUnderColumnSpanAll)
     EXPECT_EQ(columns->layer(), overflowClipObject->paintingLayer());
 }
 
+TEST_F(LayoutObjectTest, TraverseNonCompositingDescendantsInPaintOrder)
+{
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
+        return;
+
+    enableCompositing();
+    setBodyInnerHTML(
+        "<style>div { width: 10px; height: 10px; background-color: green; }</style>"
+        "<div id='container' style='position: fixed'>"
+        "  <div id='normal-child'></div>"
+        "  <div id='stacked-child' style='position: relative'></div>"
+        "  <div id='composited-stacking-context' style='will-change: transform'>"
+        "    <div id='normal-child-of-composited-stacking-context'></div>"
+        "    <div id='stacked-child-of-composited-stacking-context' style='position: relative'></div>"
+        "  </div>"
+        "  <div id='composited-non-stacking-context' style='backface-visibility: hidden'>"
+        "    <div id='normal-child-of-composited-non-stacking-context'></div>"
+        "    <div id='stacked-child-of-composited-non-stacking-context' style='position: relative'></div>"
+        "    <div id='non-stacked-layered-child-of-composited-non-stacking-context' style='overflow: scroll'></div>"
+        "  </div>"
+        "</div>");
+
+    document().view()->setTracksPaintInvalidations(true);
+    getLayoutObjectByElementId("container")->invalidateDisplayItemClientsIncludingNonCompositingDescendants(PaintInvalidationSubtree);
+    std::unique_ptr<JSONArray> invalidations = document().view()->trackedObjectPaintInvalidationsAsJSON();
+    document().view()->setTracksPaintInvalidations(false);
+
+    ASSERT_EQ(4u, invalidations->size());
+    String s;
+    JSONObject::cast(invalidations->at(0))->get("object")->asString(&s);
+    EXPECT_EQ(getLayoutObjectByElementId("container")->debugName(), s);
+    JSONObject::cast(invalidations->at(1))->get("object")->asString(&s);
+    EXPECT_EQ(getLayoutObjectByElementId("normal-child")->debugName(), s);
+    JSONObject::cast(invalidations->at(2))->get("object")->asString(&s);
+    EXPECT_EQ(getLayoutObjectByElementId("stacked-child")->debugName(), s);
+    JSONObject::cast(invalidations->at(3))->get("object")->asString(&s);
+    EXPECT_EQ(getLayoutObjectByElementId("stacked-child-of-composited-non-stacking-context")->debugName(), s);
+}
+
 } // namespace blink