Simplify subtree (now subsequence) caching

Source/platform/graphics/paint/DisplayItem.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef DisplayItem_h
 #define DisplayItem_h
 
 #include "platform/PlatformExport.h"
 #include "platform/graphics/ContiguousContainer.h"
 #include "platform/graphics/paint/DisplayItemClient.h"
@@ skipping 147 matching lines @@
         EndCompositing,
         BeginTransform,
         EndTransform,
         BeginClipPath,
         EndClipPath,
         BeginFixedPosition,
         EndFixedPosition,
         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
     };
 
     static_assert(TableCollapsedBorderBase >= TableCollapsedBorderUnalignedBase, "TableCollapsedBorder types overlap with other types");
     static_assert((TableCollapsedBorderBase & 0xf) == 0, "The lowest 4 bits of TableCollapsedBorderBase should be zero");
     // Bits or'ed onto TableCollapsedBorderBase to generate a real table collapsed border type.
     enum TableCollspaedBorderSides {
         TableCollapsedBorderTop = 1 << 0,
@@ skipping 40 matching lines @@
         const DisplayItemClient client;
         const Type type;
         const unsigned scope;
     };
 
     // Convert cached type to non-cached type (e.g., Type::CachedSVGImage -> Type::SVGImage).
     static Type nonCachedType(Type type)
     {
         if (isCachedDrawingType(type))
             return cachedDrawingTypeToDrawingType(type);
-        if (isCachedSubtreeType(type))
-            return cachedSubtreeTypeToBeginSubtreeType(type);
+        if (type == CachedSubtree)
+            return BeginSubtree;
         return type;
     }
 
     // Return the Id with cached type converted to non-cached type.
     Id nonCachedId() const
     {
         return Id(m_client, nonCachedType(m_type), m_scope);
     }
 
     virtual void replay(GraphicsContext&) { }
@@ skipping 59 matching lines @@
     DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipColumnBounds)
 
     DEFINE_PAIRED_CATEGORY_METHODS(FloatClip, floatClip)
     DEFINE_PAINT_PHASE_CONVERSION_METHOD(FloatClip)
 
     DEFINE_PAIRED_CATEGORY_METHODS(Scroll, scroll)
     DEFINE_PAINT_PHASE_CONVERSION_METHOD(Scroll)
 
     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; }
     virtual bool isEnd() const { return false; }
 
 #if ENABLE(ASSERT)
     virtual bool isEndAndPairedWith(DisplayItem::Type otherType) const { return false; }
 #endif
 
     virtual bool drawsContent() const { return false; }
@@ skipping 53 matching lines @@
     bool isEndAndPairedWith(DisplayItem::Type otherType) const override = 0;
 #endif
 
 private:
     bool isEnd() const final { return true; }
 };
 
 } // namespace blink
 
 #endif // DisplayItem_h