[Experimental] Implement some part of custom properties in style maps

third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h

Index: third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h
diff --git a/third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h b/third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h
index 7ea52a29167aa6c2502d969b05da187a2061c9f5..83bd95e831d5660982ed3ba5d2681741dea86f0d 100644
--- a/third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h
+++ b/third_party/WebKit/Source/core/css/cssom/ComputedStylePropertyMap.h
@@ -32,19 +32,13 @@ class CORE_EXPORT ComputedStylePropertyMap : public StylePropertyMapReadonly {
   Vector<String> getProperties() override;
 
   DEFINE_INLINE_VIRTUAL_TRACE() {
-    visitor->trace(m_computedStyleDeclaration);
     visitor->trace(m_node);
     StylePropertyMapReadonly::trace(visitor);
   }
 
- private:
-  Node* node() const;
-
  protected:
   ComputedStylePropertyMap(Node* node, const String& pseudoElement = String())
       : StylePropertyMapReadonly(),
-        m_computedStyleDeclaration(
-            CSSComputedStyleDeclaration::create(node, false, pseudoElement)),
         m_pseudoId(CSSSelector::parsePseudoId(pseudoElement)),
         m_node(node) {}
 
@@ -55,7 +49,9 @@ class CORE_EXPORT ComputedStylePropertyMap : public StylePropertyMapReadonly {
     return HeapVector<StylePropertyMapEntry>();
   }
 
-  Member<CSSComputedStyleDeclaration> m_computedStyleDeclaration;
+ private:
+  Node* node() const;
+
   PseudoId m_pseudoId;
   Member<Node> m_node;
 };