Simplify subtree (now subsequence) caching

Source/platform/graphics/paint/DisplayItem.h

Index: Source/platform/graphics/paint/DisplayItem.h
diff --git a/Source/platform/graphics/paint/DisplayItem.h b/Source/platform/graphics/paint/DisplayItem.h
index d3efa09053b7eefcdac06b62c2530cae3e53a8ff..eaab86c1937c04ce73dba2af72816d48fdff95a7 100644
--- a/Source/platform/graphics/paint/DisplayItem.h
+++ b/Source/platform/graphics/paint/DisplayItem.h
@@ -165,20 +165,9 @@ public:
         BeginFixedPositionContainer,
         EndFixedPositionContainer,
 
-        CachedSubtreeFirst,
-        CachedSubtreePaintPhaseFirst = CachedSubtreeFirst,
-        CachedSubtreePaintPhaseLast = CachedSubtreePaintPhaseFirst + PaintPhaseMax,
-        CachedSubtreeLast = CachedSubtreePaintPhaseLast,
-
-        BeginSubtreeFirst,
-        BeginSubtreePaintPhaseFirst = BeginSubtreeFirst,
-        BeginSubtreePaintPhaseLast = BeginSubtreePaintPhaseFirst + PaintPhaseMax,
-        BeginSubtreeLast = BeginSubtreePaintPhaseLast,
-
-        EndSubtreeFirst,
-        EndSubtreePaintPhaseFirst = EndSubtreeFirst,
-        EndSubtreePaintPhaseLast = EndSubtreePaintPhaseFirst + PaintPhaseMax,
-        EndSubtreeLast = EndSubtreePaintPhaseLast,
+        BeginSubtree,
+        EndSubtree,
+        CachedSubtree,

[chrishtr, 2015/08/25 23:48:19]

How about CachedStackingContext or some other more precise name? Alternatively,
it could be CachedSubsequence, since from another point of view, subtree is an
implementation detail.

[Xianzhu, 2015/08/26 23:21:06]

CachedSubsequence sgtm.

 
         UninitializedType,
         TypeLast = UninitializedType
@@ -239,8 +228,8 @@ public:
     {
         if (isCachedDrawingType(type))
             return cachedDrawingTypeToDrawingType(type);
-        if (isCachedSubtreeType(type))
-            return cachedSubtreeTypeToBeginSubtreeType(type);
+        if (type == CachedSubtree)
+            return BeginSubtree;
         return type;
     }
 
@@ -320,19 +309,9 @@ public:
 
     DEFINE_PAIRED_CATEGORY_METHODS(Transform3D, transform3D);
 
-    DEFINE_CATEGORY_METHODS(CachedSubtree)
-    DEFINE_PAINT_PHASE_CONVERSION_METHOD(CachedSubtree)
-    DEFINE_CATEGORY_METHODS(BeginSubtree)
-    DEFINE_PAINT_PHASE_CONVERSION_METHOD(BeginSubtree)
-    DEFINE_CATEGORY_METHODS(EndSubtree)
-    DEFINE_PAINT_PHASE_CONVERSION_METHOD(EndSubtree)
-    DEFINE_CONVERSION_METHODS(CachedSubtree, cachedSubtree, BeginSubtree, beginSubtree)
-    DEFINE_CONVERSION_METHODS(CachedSubtree, cachedSubtree, EndSubtree, endSubtree)
-    DEFINE_CONVERSION_METHODS(BeginSubtree, beginSubtree, EndSubtree, endSubtree)
-
-    static bool isCachedType(Type type) { return isCachedDrawingType(type) || isCachedSubtreeType(type); }
+    static bool isCachedType(Type type) { return isCachedDrawingType(type) || type == CachedSubtree; }
     bool isCached() const { return isCachedType(m_type); }
-    static bool isCacheableType(Type type) { return isDrawingType(type) || isBeginSubtreeType(type); }
+    static bool isCacheableType(Type type) { return isDrawingType(type) || type == BeginSubtree; }
     bool isCacheable() const { return !skippedCache() && isCacheableType(m_type); }
 
     virtual bool isBegin() const { return false; }