Implement incremental paint property tree rebuilding

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

 // Copyright 2015 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 EffectPaintPropertyNode_h
 #define EffectPaintPropertyNode_h
 
 #include "platform/PlatformExport.h"
 #include "platform/graphics/CompositorFilterOperations.h"
 #include "wtf/PassRefPtr.h"
@@ skipping 42 matching lines @@
   }
   const ClipPaintPropertyNode* outputClip() const { return m_outputClip.get(); }
 
   float opacity() const { return m_opacity; }
   const CompositorFilterOperations& filter() const { return m_filter; }
 
   // Parent effect or nullptr if this is the root effect.
   const EffectPaintPropertyNode* parent() const { return m_parent.get(); }
   bool isRoot() const { return !m_parent; }
 
+#if DCHECK_IS_ON()
+  // The clone function is used by FindPropertiesNeedingUpdate.h for recording
+  // an effect node before it has been updated, to later detect changes.
+  PassRefPtr<EffectPaintPropertyNode> clone() const {
+    return adoptRef(new EffectPaintPropertyNode(
+        m_parent, m_localTransformSpace, m_outputClip, m_filter, m_opacity));
+  }
+
+  // The equality operator is used by FindPropertiesNeedingUpdate.h for checking
+  // if an effect node has changed.
+  bool operator==(const EffectPaintPropertyNode& o) const {
+    return m_parent == o.m_parent &&
+           m_localTransformSpace == o.m_localTransformSpace &&
+           m_outputClip == o.m_outputClip && m_filter == o.m_filter &&
+           m_opacity == o.m_opacity;
+  }
+#endif
+
  private:
   EffectPaintPropertyNode(
       PassRefPtr<const EffectPaintPropertyNode> parent,
       PassRefPtr<const TransformPaintPropertyNode> localTransformSpace,
       PassRefPtr<const ClipPaintPropertyNode> outputClip,
       CompositorFilterOperations filter,
       float opacity)
       : m_parent(parent),
         m_localTransformSpace(localTransformSpace),
         m_outputClip(outputClip),
@@ skipping 19 matching lines @@
   // === End of effects ===
 };
 
 // Redeclared here to avoid ODR issues.
 // See platform/testing/PaintPrinters.h.
 void PrintTo(const EffectPaintPropertyNode&, std::ostream*);
 
 }  // namespace blink
 
 #endif  // EffectPaintPropertyNode_h