Reuse existing paint property node is possible

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

Index: third_party/WebKit/Source/platform/graphics/paint/EffectPaintPropertyNode.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/EffectPaintPropertyNode.h b/third_party/WebKit/Source/platform/graphics/paint/EffectPaintPropertyNode.h
index 46cf9c510567796faa2fbd4a8f93fd7ca55a4cd5..d0d51bfbf7170e51ff9963fc4d53911600e7fa46 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/EffectPaintPropertyNode.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/EffectPaintPropertyNode.h
@@ -19,16 +19,22 @@ namespace blink {
 // TODO(pdr): Support more effects than just opacity.
 class PLATFORM_EXPORT EffectPaintPropertyNode : public RefCounted<EffectPaintPropertyNode> {
 public:
+    using Value = float;
+
     static PassRefPtr<EffectPaintPropertyNode> create(float opacity, PassRefPtr<EffectPaintPropertyNode> parent = nullptr)
     {
         return adoptRef(new EffectPaintPropertyNode(opacity, parent));
     }
 
+    Value value() const { return m_opacity; }
     float opacity() const { return m_opacity; }
 
     // Parent effect or nullptr if this is the root effect.
     const EffectPaintPropertyNode* parent() const { return m_parent.get(); }
 
+    // Moves this node and its subtrees under another parent.
+    void setParent(PassRefPtr<EffectPaintPropertyNode> parent) { m_parent = parent; }
+
 private:
     EffectPaintPropertyNode(float opacity, PassRefPtr<EffectPaintPropertyNode> parent)
         : m_opacity(opacity), m_parent(parent) { }