[SPv2] Defer decision of raster invalidation after paint for changes z-index, transform, etc.

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

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
index c7ecf68b4cf1047b58b55e0c380c628430fdcc0c..95361b6e8a68ed2837ea25c5c4889862c323d715 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItemList.cpp
@@ -19,12 +19,12 @@ DisplayItem& DisplayItemList::appendByMoving(DisplayItem& item)
 #ifndef NDEBUG
     String originalDebugString = item.asDebugString();
 #endif
-    ASSERT(item.hasValidClient());
-    DisplayItem& result = ContiguousContainer::appendByMoving(item, item.derivedSize());
+    DCHECK(!item.hasBeenMoved());
+    DisplayItem& result = ContiguousContainer::appendByMoving(item, item.derivedSize(), size());
     // ContiguousContainer::appendByMoving() calls an in-place constructor
-    // on item which replaces it with a tombstone/"dead display item" that
-    // can be safely destructed but should never be used.
-    ASSERT(!item.hasValidClient());
+    // DisplayItem(size_t) to create a placeholder of type HasBeenMoved in
+    // place of the original item.
+    DCHECK(item.hasBeenMoved());
 #ifndef NDEBUG
     // Save original debug string in the old item to help debugging.
     item.setClientDebugString(originalDebugString);