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

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

Index: third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h b/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
index 35e1c414162c22fa4b24b1096f2952386b21678f..2670d444a6c168c0bc13146840590e1e229e68de 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/DisplayItem.h
@@ -168,14 +168,9 @@ public:
         BeginFixedPositionContainer,
         EndFixedPositionContainer,
 
-        SubsequenceFirst,
-        SubsequenceNegativeZOrder = SubsequenceFirst,
-        SubsequenceNormalFlowAndPositiveZOrder,
-        SubsequenceLast = SubsequenceNormalFlowAndPositiveZOrder,
-        EndSubsequenceFirst,
-        EndSubsequenceLast = EndSubsequenceFirst + SubsequenceLast - SubsequenceFirst,
-        CachedSubsequenceFirst,
-        CachedSubsequenceLast = CachedSubsequenceFirst + SubsequenceLast - SubsequenceFirst,
+        Subsequence,
+        EndSubsequence,
+        CachedSubsequence,
 
         CachedDisplayItemList,
 
@@ -238,8 +233,8 @@ public:
     {
         if (isCachedDrawingType(type))
             return cachedDrawingTypeToDrawingType(type);
-        if (isCachedSubsequenceType(type))
-            return cachedSubsequenceTypeToSubsequenceType(type);
+        if (type == CachedSubsequence)
+            return Subsequence;
         return type;
     }
 
@@ -319,13 +314,9 @@ public:
 
     DEFINE_PAIRED_CATEGORY_METHODS(Transform3D, transform3D)
 
-    DEFINE_PAIRED_CATEGORY_METHODS(Subsequence, subsequence)
-    DEFINE_CATEGORY_METHODS(CachedSubsequence)
-    DEFINE_CONVERSION_METHODS(Subsequence, subsequence, CachedSubsequence, cachedSubsequence)
-
-    static bool isCachedType(Type type) { return isCachedDrawingType(type) || isCachedSubsequenceType(type) || type == CachedDisplayItemList; }
+    static bool isCachedType(Type type) { return isCachedDrawingType(type) || type == CachedSubsequence || type == CachedDisplayItemList; }
     bool isCached() const { return isCachedType(m_type); }
-    static bool isCacheableType(Type type) { return isDrawingType(type) || isSubsequenceType(type); }
+    static bool isCacheableType(Type type) { return isDrawingType(type) || type == Subsequence; }
     bool isCacheable() const { return !skippedCache() && isCacheableType(m_type); }
 
     virtual bool isBegin() const { return false; }