Subtree caching implementation in blink-core

Source/platform/graphics/paint/DisplayItemListTest.cpp

Index: Source/platform/graphics/paint/DisplayItemListTest.cpp
diff --git a/Source/platform/graphics/paint/DisplayItemListTest.cpp b/Source/platform/graphics/paint/DisplayItemListTest.cpp
index 59e7642e15a0df630c18a0e3f31dec68c67c752b..f7078500ea3beb13f779406f3d4cc04040f506ae 100644
--- a/Source/platform/graphics/paint/DisplayItemListTest.cpp
+++ b/Source/platform/graphics/paint/DisplayItemListTest.cpp
@@ -463,25 +463,21 @@ TEST_F(DisplayItemListTest, CachedSubtreeSwapOrder)
 
     {
         SubtreeRecorder r(context, container1, backgroundPaintPhase);
-        EXPECT_FALSE(r.canUseCache());
         drawRect(context, container1, backgroundDrawingType, FloatRect(100, 100, 100, 100));
         drawRect(context, content1, backgroundDrawingType, FloatRect(100, 100, 50, 200));
     }
     {
         SubtreeRecorder r(context, container1, foregroundPaintPhase);
-        EXPECT_FALSE(r.canUseCache());
         drawRect(context, content1, foregroundDrawingType, FloatRect(100, 100, 50, 200));
         drawRect(context, container1, foregroundDrawingType, FloatRect(100, 100, 100, 100));
     }
     {
         SubtreeRecorder r(context, container2, backgroundPaintPhase);
-        EXPECT_FALSE(r.canUseCache());
         drawRect(context, container2, backgroundDrawingType, FloatRect(100, 200, 100, 100));
         drawRect(context, content2, backgroundDrawingType, FloatRect(100, 200, 50, 200));
     }
     {
         SubtreeRecorder r(context, container2, foregroundPaintPhase);
-        EXPECT_FALSE(r.canUseCache());
         drawRect(context, content2, foregroundDrawingType, FloatRect(100, 200, 50, 200));
         drawRect(context, container2, foregroundDrawingType, FloatRect(100, 200, 100, 100));
     }
@@ -509,17 +505,17 @@ TEST_F(DisplayItemListTest, CachedSubtreeSwapOrder)
         TestDisplayItem(container2, DisplayItem::paintPhaseToEndSubtreeType(foregroundPaintPhase)));
 
     // Simulate the situation when container1 e.g. gets a z-index that is now greater than container2.
-    displayItemList().createAndAppend<CachedDisplayItem>(container2, DisplayItem::paintPhaseToCachedSubtreeType(backgroundPaintPhase));
+    EXPECT_TRUE(SubtreeRecorder::useCachedSubtreeIfPossible(context, container2, backgroundPaintPhase));
     EXPECT_EQ((size_t)1, newPaintListBeforeUpdate().size());
     EXPECT_TRUE(newPaintListBeforeUpdate().last().isCachedSubtree());
-    displayItemList().createAndAppend<CachedDisplayItem>(container2, DisplayItem::paintPhaseToCachedSubtreeType(foregroundPaintPhase));
+    EXPECT_TRUE(SubtreeRecorder::useCachedSubtreeIfPossible(context, container2, foregroundPaintPhase));
     EXPECT_EQ((size_t)2, newPaintListBeforeUpdate().size());
     EXPECT_TRUE(newPaintListBeforeUpdate().last().isCachedSubtree());
 
-    displayItemList().createAndAppend<CachedDisplayItem>(container1, DisplayItem::paintPhaseToCachedSubtreeType(backgroundPaintPhase));
+    EXPECT_TRUE(SubtreeRecorder::useCachedSubtreeIfPossible(context, container1, backgroundPaintPhase));
     EXPECT_EQ((size_t)3, newPaintListBeforeUpdate().size());
     EXPECT_TRUE(newPaintListBeforeUpdate().last().isCachedSubtree());
-    displayItemList().createAndAppend<CachedDisplayItem>(container1, DisplayItem::paintPhaseToCachedSubtreeType(foregroundPaintPhase));
+    EXPECT_TRUE(SubtreeRecorder::useCachedSubtreeIfPossible(context, container1, foregroundPaintPhase));
     EXPECT_EQ((size_t)4, newPaintListBeforeUpdate().size());
     EXPECT_TRUE(newPaintListBeforeUpdate().last().isCachedSubtree());
     displayItemList().commitNewDisplayItems();