First version of new merge algorithm (not enabled yet)

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/paint/DisplayItemClient.h"
 #include "wtf/Assertions.h"
@@ skipping 103 matching lines @@
         EndScrollLast = EndScrollFirst + ScrollLast - ScrollFirst,
 
         BeginFilter,
         EndFilter,
         BeginCompositing,
         EndCompositing,
         BeginTransform,
         EndTransform,
         BeginClipPath,
         EndClipPath,
+
+        SubtreeCachedFirst,
+        SubtreeCachedPaintPhaseFirst = SubtreeCachedFirst,
+        SubtreeCachedPaintPhaseLast = SubtreeCachedPaintPhaseFirst + PaintPhaseMax,
+        SubtreeCachedLast = SubtreeCachedPaintPhaseLast,
+
+        BeginSubtreeFirst,
+        BeginSubtreePaintPhaseFirst = BeginSubtreeFirst,
+        BeginSubtreePaintPhaseLast = BeginSubtreePaintPhaseFirst + PaintPhaseMax,
+        BeginSubtreeLast = BeginSubtreePaintPhaseLast,
+
+        EndSubtreeFirst,
+        EndSubtreePaintPhaseFirst = EndSubtreeFirst,
+        EndSubtreePaintPhaseLast = EndSubtreePaintPhaseFirst + PaintPhaseMax,
+        EndSubtreeLast = EndSubtreePaintPhaseLast,
     };
 
-    // Create a dummy display item which just holds the id but has no display operation.
-    // It helps a CachedDisplayItem to match the corresponding original empty display item.
-    static PassOwnPtr<DisplayItem> create(DisplayItemClient client, Type type) { return adoptPtr(new DisplayItem(client, type)); }
-
     virtual ~DisplayItem() { }
 
     virtual void replay(GraphicsContext*) { }
 
     DisplayItemClient client() const { return m_id.client; }
     Type type() const { return m_id.type; }
     bool idsEqual(const DisplayItem& other) const { return m_id.client == other.m_id.client && m_id.type == other.m_id.type; }
 
     virtual void appendToWebDisplayItemList(WebDisplayItemList*) const { }
 
@@ skipping 38 matching lines @@
     DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipLayerFragment)
     DEFINE_PAINT_PHASE_CONVERSION_METHOD(ClipBox)
     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_CATEGORY_METHODS(SubtreeCached)
+    DEFINE_PAINT_PHASE_CONVERSION_METHOD(SubtreeCached)
+    DEFINE_CATEGORY_METHODS(BeginSubtree)
+    DEFINE_PAINT_PHASE_CONVERSION_METHOD(BeginSubtree)
+    DEFINE_CATEGORY_METHODS(EndSubtree)
+    DEFINE_PAINT_PHASE_CONVERSION_METHOD(EndSubtree)
+    DEFINE_CONVERSION_METHODS(SubtreeCached, subtreeCached, BeginSubtree, beginSubtree)
+    DEFINE_CONVERSION_METHODS(SubtreeCached, subtreeCached, EndSubtree, endSubtree)
+    DEFINE_CONVERSION_METHODS(BeginSubtree, beginSubtree, EndSubtree, endSubtree)
+
     virtual bool isBegin() const { return false; }
     virtual bool isEnd() const { return false; }
 
 #if ENABLE(ASSERT)
     virtual bool isEndAndPairedWith(const DisplayItem& other) const { return false; }
 #endif
 
 #ifndef NDEBUG
     static WTF::String typeAsDebugString(DisplayItem::Type);
 
@@ skipping 44 matching lines @@
     virtual bool isEndAndPairedWith(const DisplayItem& other) const override = 0;
 #endif
 
 private:
     virtual bool isEnd() const override final { return true; }
 };
 
 } // namespace blink
 
 #endif // DisplayItem_h