New display item caching

Source/core/paint/ViewDisplayListTest.cpp

 // Copyright 2014 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 "config.h"
 
 #include "core/paint/LayerClipRecorder.h"
 #include "core/paint/LayerPainter.h"
 #include "core/paint/RenderDrawingRecorder.h"
+#include "core/paint/SubtreeInfoRecorder.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderingTestHelper.h"
 #include "core/rendering/compositing/RenderLayerCompositor.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DisplayItemList.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include <gtest/gtest.h>
 
 namespace blink {
@@ skipping 15 matching lines @@
         RenderingTest::SetUp();
         enableCompositing();
 
         m_renderView = document().view()->renderView();
         ASSERT_TRUE(m_renderView);
     }
 
     virtual void TearDown() override
     {
         RuntimeEnabledFeatures::setSlimmingPaintEnabled(false);
-        RuntimeEnabledFeatures::setSlimmingPaintDisplayItemCacheEnabled(false);
     }
 
     RenderView* m_renderView;
 };
 
 class TestDisplayItem : public DisplayItem {
 public:
     TestDisplayItem(const RenderObject* renderer, Type type) : DisplayItem(renderer->displayItemClient(), type) { }
 
     virtual void replay(GraphicsContext*) override final { ASSERT_NOT_REACHED(); }
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const override final { ASSERT_NOT_REACHED(); }
 #ifndef NDEBUG
     virtual const char* name() const override final { return "Test"; }
 #endif
 };
 
 #ifndef NDEBUG
-#define TRACE_DISPLAY_ITEMS(expected, actual) \
-    String trace = "Expected: " + (expected).asDebugString() + " Actual: " + (actual).asDebugString(); \
+#define TRACE_DISPLAY_ITEMS(i, expected, actual) \
+    String trace = String::format("%d: ", (int)i) + "Expected: " + (expected).asDebugString() + " Actual: " + (actual).asDebugString(); \
     SCOPED_TRACE(trace.utf8().data());
 #else
 #define TRACE_DISPLAY_ITEMS(expected, actual)
 #endif
 
 #define EXPECT_DISPLAY_LIST(actual, expectedSize, ...) { \
     EXPECT_EQ((size_t)expectedSize, actual.size()); \
     const TestDisplayItem expected[] = { __VA_ARGS__ }; \
     for (size_t index = 0; index < std::min<size_t>(actual.size(), expectedSize); index++) { \
-        TRACE_DISPLAY_ITEMS(expected[index], *actual[index]); \
+        TRACE_DISPLAY_ITEMS(index, expected[index], *actual[index]); \
         EXPECT_EQ(expected[index].client(), actual[index]->client()); \
         EXPECT_EQ(expected[index].type(), actual[index]->type()); \
     } \
 }
 
 void drawRect(GraphicsContext* context, RenderObject* renderer, PaintPhase phase, const FloatRect& bound)
 {
     RenderDrawingRecorder drawingRecorder(context, *renderer, phase, bound);
     if (drawingRecorder.canUseCachedDrawing())
         return;
     IntRect rect(0, 0, 10, 10);
     context->drawRect(rect);
 }
 
 void drawClippedRect(GraphicsContext* context, RenderLayerModelObject* renderer, PaintPhase phase, const FloatRect& bound)
 {
     IntRect rect(1, 1, 9, 9);
     ClipRect clipRect(rect);
     LayerClipRecorder layerClipRecorder(renderer, context, DisplayItem::ClipLayerForeground, clipRect, 0, LayoutPoint(), PaintLayerFlags());
     drawRect(context, renderer, phase, bound);
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_NestedRecorders)
+TEST_F(ViewDisplayListTest, NestedRecorders)
 {
     GraphicsContext context(nullptr, &rootDisplayItemList());
     FloatRect bound = renderView()->viewRect();
 
     drawClippedRect(&context, renderView(), PaintPhaseForeground, bound);
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(renderView(), DisplayItem::ClipLayerForeground),
         TestDisplayItem(renderView(), DisplayItem::DrawingPaintPhaseForeground),
         TestDisplayItem(renderView(), DisplayItem::EndClip));
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateBasic)
+TEST_F(ViewDisplayListTest, UpdateBasic)
 {
     setBodyInnerHTML("<div id='first'><div id='second'></div></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->firstChild()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 300, 300));
     drawRect(&context, second, PaintPhaseChildBlockBackground, FloatRect(100, 100, 200, 200));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 300, 300));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseChildBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
 
     rootDisplayItemList().invalidate(second->displayItemClient());
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 300, 300));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 300, 300));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateSwapOrder)
+TEST_F(ViewDisplayListTest, UpdateSwapOrder)
 {
     setBodyInnerHTML("<div id='first'><div id='second'></div></div><div id='unaffected'></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->firstChild()->renderer();
     RenderObject* unaffected = document().body()->firstChild()->nextSibling()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
     drawRect(&context, unaffected, PaintPhaseBlockBackground, FloatRect(300, 300, 10, 10));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(unaffected, DisplayItem::DrawingPaintPhaseBlockBackground));
 
     rootDisplayItemList().invalidate(second->displayItemClient());
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
     drawRect(&context, unaffected, PaintPhaseBlockBackground, FloatRect(300, 300, 10, 10));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(unaffected, DisplayItem::DrawingPaintPhaseBlockBackground));
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateNewItemInMiddle)
+TEST_F(ViewDisplayListTest, UpdateNewItemInMiddle)
 {
     setBodyInnerHTML("<div id='first'><div id='second'><div id='third'></div></div></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->firstChild()->renderer();
     RenderObject* third = document().body()->firstChild()->firstChild()->firstChild()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground));
 
     rootDisplayItemList().invalidate(third->displayItemClient());
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
     drawRect(&context, third, PaintPhaseBlockBackground, FloatRect(125, 100, 200, 50));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(third, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground));
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateInvalidationWithPhases)
+TEST_F(ViewDisplayListTest, UpdateInvalidationWithPhases)
 {
     setBodyInnerHTML("<div id='first'><div id='second'></div></div><div id='third'></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->firstChild()->renderer();
     RenderObject* third = document().body()->firstChild()->nextSibling()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
     drawRect(&context, third, PaintPhaseBlockBackground, FloatRect(300, 100, 50, 50));
@@ skipping 46 matching lines @@
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 6,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(third, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseForeground),
         TestDisplayItem(third, DisplayItem::DrawingPaintPhaseForeground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline),
         TestDisplayItem(third, DisplayItem::DrawingPaintPhaseOutline));
 #endif
 }
 
-// This test is only applicable when we support incremental paint.
-TEST_F(ViewDisplayListTest, DISABLED_ViewDisplayListTest_UpdateAddFirstNoOverlap)
+TEST_F(ViewDisplayListTest, UpdateAddFirstOverlap)
 {
     setBodyInnerHTML("<div id='first'></div><div id='second'></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
-    RenderObject* second = document().body()->firstChild()->nextSibling()->renderer();
-    GraphicsContext context(nullptr, &rootDisplayItemList());
-
-    drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
-    drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
-
-    rootDisplayItemList().invalidate(first->displayItemClient());
-    drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 50));
-    drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 50, 50));
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 4,
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline),
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
-
-    rootDisplayItemList().invalidate(first->displayItemClient());
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
-}
-
-// This test is only applicable when we support incremental paint.
-TEST_F(ViewDisplayListTest, DISABLED_ViewDisplayListTest_UpdateAddFirstOverlap)
-{
-    setBodyInnerHTML("<div id='first'></div><div id='second'></div>");
-    RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->nextSibling()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
     drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
 
     rootDisplayItemList().invalidate(first->displayItemClient());
     rootDisplayItemList().invalidate(second->displayItemClient());
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 150, 150));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
     drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 4,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
 
     rootDisplayItemList().invalidate(first->displayItemClient());
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
     drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
 }
 
-// This test is only applicable when we support incremental paint.
-TEST_F(ViewDisplayListTest, DISABLED_ViewDisplayListTest_UpdateAddLastNoOverlap)
+TEST_F(ViewDisplayListTest, UpdateAddLastOverlap)
 {
     setBodyInnerHTML("<div id='first'></div><div id='second'></div>");
     RenderObject* first = document().body()->firstChild()->renderer();
-    RenderObject* second = document().body()->firstChild()->nextSibling()->renderer();
-    GraphicsContext context(nullptr, &rootDisplayItemList());
-
-    drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 50));
-    drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 50, 50));
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
-
-    rootDisplayItemList().invalidate(second->displayItemClient());
-    drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
-    drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 4,
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline),
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
-
-    rootDisplayItemList().invalidate(second->displayItemClient());
-
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
-}
-
-// This test is only applicable when we support incremental paint.
-TEST_F(ViewDisplayListTest, DISABLED_ViewDisplayListTest_UpdateAddLastOverlap)
-{
-    setBodyInnerHTML("<div id='first'></div><div id='second'></div>");
-    RenderObject* first = document().body()->firstChild()->renderer();
     RenderObject* second = document().body()->firstChild()->nextSibling()->renderer();
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 150, 150));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
 
     rootDisplayItemList().invalidate(first->displayItemClient());
     rootDisplayItemList().invalidate(second->displayItemClient());
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 150, 150));
     drawRect(&context, second, PaintPhaseBlockBackground, FloatRect(200, 200, 50, 50));
     drawRect(&context, second, PaintPhaseOutline, FloatRect(200, 200, 50, 50));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 4,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(second, DisplayItem::DrawingPaintPhaseOutline));
 
     rootDisplayItemList().invalidate(first->displayItemClient());
     rootDisplayItemList().invalidate(second->displayItemClient());
     drawRect(&context, first, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     drawRect(&context, first, PaintPhaseOutline, FloatRect(100, 100, 150, 150));
+    rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(first, DisplayItem::DrawingPaintPhaseOutline));
 }
 
-TEST_F(ViewDisplayListTest, ViewDisplayListTest_UpdateClip)
+TEST_F(ViewDisplayListTest, UpdateClip)
 {
     setBodyInnerHTML("<div id='first'><div id='second'></div></div>");
     RenderLayerModelObject* firstRenderer = toRenderLayerModelObject(document().body()->firstChild()->renderer());
     RenderLayerModelObject* secondRenderer = toRenderLayerModelObject(document().body()->firstChild()->firstChild()->renderer());
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     ClipRect firstClipRect(IntRect(1, 1, 2, 2));
     {
         LayerClipRecorder layerClipRecorder(firstRenderer, &context, DisplayItem::ClipLayerForeground, firstClipRect, 0, LayoutPoint(), PaintLayerFlags());
         drawRect(&context, firstRenderer, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
@@ skipping 27 matching lines @@
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 4,
         TestDisplayItem(firstRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(secondRenderer, DisplayItem::ClipLayerForeground),
         TestDisplayItem(secondRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(secondRenderer, DisplayItem::EndClip));
 }
 
 TEST_F(ViewDisplayListTest, CachedDisplayItems)
 {
-    RuntimeEnabledFeatures::setSlimmingPaintDisplayItemCacheEnabled(true);
-
     setBodyInnerHTML("<div id='first'><div id='second'></div></div>");
     RenderLayerModelObject* firstRenderer = toRenderLayerModelObject(document().body()->firstChild()->renderer());
     RenderLayerModelObject* secondRenderer = toRenderLayerModelObject(document().body()->firstChild()->firstChild()->renderer());
     GraphicsContext context(nullptr, &rootDisplayItemList());
 
     drawRect(&context, firstRenderer, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     drawRect(&context, secondRenderer, PaintPhaseBlockBackground, FloatRect(100, 100, 150, 150));
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
@@ skipping 26 matching lines @@
     EXPECT_FALSE(rootDisplayItemList().clientCacheIsValid(firstRenderer->displayItemClient()));
     EXPECT_FALSE(rootDisplayItemList().clientCacheIsValid(secondRenderer->displayItemClient()));
 }
 
 TEST_F(ViewDisplayListTest, FullDocumentPaintingWithCaret)
 {
     setBodyInnerHTML("<div id='div' contentEditable='true'>XYZ</div>");
     RenderView* renderView = document().renderView();
     RenderLayer* rootLayer = renderView->layer();
     RenderObject* htmlRenderer = document().documentElement()->renderer();
+    showRenderTree(htmlRenderer);
+    RenderObject* bodyRenderer = document().body()->renderer();
     Element* div = toElement(document().body()->firstChild());
     RenderObject* divRenderer = document().body()->firstChild()->renderer();
     RenderObject* textRenderer = div->firstChild()->renderer();
 
     SkCanvas canvas(800, 600);
     GraphicsContext context(&canvas, &rootDisplayItemList());
     LayerPaintingInfo paintingInfo(rootLayer, LayoutRect(0, 0, 800, 600), PaintBehaviorNormal, LayoutSize());
     LayerPainter(*rootLayer).paintLayerContents(&context, paintingInfo, PaintLayerPaintingCompositingAllPhases);
     rootDisplayItemList().endNewPaints();
 
-    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 2,
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 17,
+        TestDisplayItem(renderView, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(htmlRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
-        TestDisplayItem(textRenderer, DisplayItem::DrawingPaintPhaseForeground));
+        TestDisplayItem(bodyRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(bodyRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(htmlRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(renderView, DisplayItem::DrawingPaintPhaseBlockBackground),
+
+        TestDisplayItem(renderView, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(htmlRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(bodyRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(textRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(bodyRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(htmlRenderer, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(renderView, DisplayItem::DrawingPaintPhaseForeground));
 
     div->focus();
     document().view()->updateLayoutAndStyleForPainting();
     LayerPainter(*rootLayer).paintLayerContents(&context, paintingInfo, PaintLayerPaintingCompositingAllPhases);
     rootDisplayItemList().endNewPaints();
 
     EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 3,
         TestDisplayItem(htmlRenderer, DisplayItem::DrawingPaintPhaseBlockBackground),
         TestDisplayItem(textRenderer, DisplayItem::DrawingPaintPhaseForeground),
         TestDisplayItem(divRenderer, DisplayItem::DrawingPaintPhaseCaret));
 }
 
+TEST_F(ViewDisplayListTest, ComplexUpdateSwapOrder)
+{
+    setBodyInnerHTML("<div id='container1'><div id='content1'></div></div>"
+        "<div id='container2'><div id='content2'></div></div>");
+    RenderObject* container1 = document().body()->firstChild()->renderer();
+    RenderObject* content1 = document().body()->firstChild()->firstChild()->renderer();
+    RenderObject* container2 = document().body()->firstChild()->nextSibling()->renderer();
+    RenderObject* content2 = document().body()->firstChild()->nextSibling()->firstChild()->renderer();
+    GraphicsContext context(nullptr, &rootDisplayItemList());
+
+    drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, container2, PaintPhaseBlockBackground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, content2, PaintPhaseBlockBackground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, content2, PaintPhaseForeground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, container2, PaintPhaseForeground, FloatRect(100, 200, 100, 100));
+    rootDisplayItemList().endNewPaints();
+
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 8,
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground));
+
+    // Simulate the situation when container1 e.g. gets a z-index that is now greater than container2.
+    rootDisplayItemList().invalidate(container1->displayItemClient());
+    drawRect(&context, container2, PaintPhaseBlockBackground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, content2, PaintPhaseBlockBackground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, content2, PaintPhaseForeground, FloatRect(100, 200, 50, 200));
+    drawRect(&context, container2, PaintPhaseForeground, FloatRect(100, 200, 100, 100));
+    drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+    drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+    drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    rootDisplayItemList().endNewPaints();
+
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 8,
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground));
+}
+
+TEST_F(ViewDisplayListTest, CachedSubtreeSwapOrder)
+{
+    setBodyInnerHTML("<div id='container1'><div id='content1'></div></div>"
+        "<div id='container2'><div id='content2'></div></div>");
+    RenderObject* container1 = document().body()->firstChild()->renderer();
+    RenderObject* content1 = document().body()->firstChild()->firstChild()->renderer();
+    RenderObject* container2 = document().body()->firstChild()->nextSibling()->renderer();
+    RenderObject* content2 = document().body()->firstChild()->nextSibling()->firstChild()->renderer();
+    GraphicsContext context(nullptr, &rootDisplayItemList());
+
+    {
+        SubtreeInfoRecorder r(&context, *container1, PaintPhaseBlockBackground);
+        r.begin();
+        drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+        drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container1, PaintPhaseForeground);
+        r.begin();
+        drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+        drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container2, PaintPhaseBlockBackground);
+        r.begin();
+        drawRect(&context, container2, PaintPhaseBlockBackground, FloatRect(100, 200, 100, 100));
+        drawRect(&context, content2, PaintPhaseBlockBackground, FloatRect(100, 200, 50, 200));
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container2, PaintPhaseForeground);
+        r.begin();
+        drawRect(&context, content2, PaintPhaseForeground, FloatRect(100, 200, 50, 200));
+        drawRect(&context, container2, PaintPhaseForeground, FloatRect(100, 200, 100, 100));
+    }
+    rootDisplayItemList().endNewPaints();
+
+    // FIXME: Too many empty BeginSubtree and EndSubtree pairs.
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 16,
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground), // BeginSubtree
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground), // EndSubtree
+
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground), // BeginSubtree
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground), // EndSubtree
+
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground), // BeginSubtree
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground), // EndSubtree
+
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground), // BeginSubtree
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground)); // EndSubtree
+
+    // Simulate the situation when container1 e.g. gets a z-index that is now greater than container2,
+    // and at the same time container2 is scrolled out of viewport.
+    {
+        SubtreeInfoRecorder r(&context, *container2, PaintPhaseBlockBackground);
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container2, PaintPhaseForeground);
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container1, PaintPhaseBlockBackground);
+        r.begin();
+        drawRect(&context, container1, PaintPhaseBlockBackground, FloatRect(100, 100, 100, 100));
+        drawRect(&context, content1, PaintPhaseBlockBackground, FloatRect(100, 100, 50, 200));
+    }
+    {
+        SubtreeInfoRecorder r(&context, *container1, PaintPhaseForeground);
+        r.begin();
+        drawRect(&context, content1, PaintPhaseForeground, FloatRect(100, 100, 50, 200));
+        drawRect(&context, container1, PaintPhaseForeground, FloatRect(100, 100, 100, 100));
+    }
+    rootDisplayItemList().endNewPaints();
+
+    EXPECT_DISPLAY_LIST(rootDisplayItemList().paintList(), 16,
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground), // BeginSubtree
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseBlockBackground), // EndSubtree
+
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground), // BeginSubtree
+        TestDisplayItem(content2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container2, DisplayItem::DrawingPaintPhaseForeground), // EndSubtree
+
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground), // BeginSubtree
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseBlockBackground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseBlockBackground), // EndSubtree
+
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground), // BeginSubtree
+        TestDisplayItem(content1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground),
+        TestDisplayItem(container1, DisplayItem::DrawingPaintPhaseForeground)); // EndSubtree
+}
+
 } // anonymous namespace
 } // namespace blink