Separate display item clients for negative and normal/positive z-order children

third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h

Index: third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h b/third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h
index dc7f45138bdf87597e6238b4d445cd73d543d311..140ff4d0c213fe165b7b9dbda8c01804b5f20893 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/SubsequenceDisplayItem.h
@@ -13,25 +13,21 @@ namespace blink {
 
 class BeginSubsequenceDisplayItem final : public PairedBeginDisplayItem {
 public:
-    BeginSubsequenceDisplayItem(const DisplayItemClientWrapper& client, DisplayItem::Type type)
-        : PairedBeginDisplayItem(client, type, sizeof(*this))
-    {
-        ASSERT(DisplayItem::isSubsequenceType(type));
-    }
+    BeginSubsequenceDisplayItem(const DisplayItemClientWrapper& client)
+        : PairedBeginDisplayItem(client, Subsequence, sizeof(*this))
+    { }
 };
 
 class EndSubsequenceDisplayItem final : public PairedEndDisplayItem {
 public:
-    EndSubsequenceDisplayItem(const DisplayItemClientWrapper& client, DisplayItem::Type type)
-        : PairedEndDisplayItem(client, type, sizeof(*this))
-    {
-        ASSERT(DisplayItem::isEndSubsequenceType(type));
-    }
+    EndSubsequenceDisplayItem(const DisplayItemClientWrapper& client)
+        : PairedEndDisplayItem(client, EndSubsequence, sizeof(*this))
+    { }
 
 #if ENABLE(ASSERT)
     bool isEndAndPairedWith(DisplayItem::Type otherType) const final
     {
-        return otherType == DisplayItem::endSubsequenceTypeToSubsequenceType(type());
+        return type() == EndSubsequence && otherType == Subsequence;
     }
 #endif
 };