[CSS Typed OM] Refactor is2D handling in CSSTransformComponents to match new spec

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

 // Copyright 2016 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 CSSPerspective_h
 #define CSSPerspective_h
 
 #include "core/CoreExport.h"
 #include "core/css/cssom/CSSNumericValue.h"
 #include "core/css/cssom/CSSTransformComponent.h"
@@ skipping 14 matching lines @@
   // Constructor defined in the IDL.
   static CSSPerspective* Create(CSSNumericValue*, ExceptionState&);
 
   // Blink-internal ways of creating CSSPerspectives.
   static CSSPerspective* FromCSSValue(const CSSFunctionValue&);
 
   // Getters and setters for attributes defined in the IDL.
   CSSNumericValue* length() { return length_.Get(); }
   void setLength(CSSNumericValue*, ExceptionState&);
 
+  // From CSSTransformComponent
+  // Setting is2D for CSSPerspective does nothing.
+  // https://drafts.css-houdini.org/css-typed-om/#dom-cssskew-is2d
+  void setIs2D(bool is2D) final {}
+
   // Internal methods - from CSSTransformComponent.
   TransformComponentType GetType() const final { return kPerspectiveType; }
   // TODO: Implement AsMatrix for CSSPerspective.
   DOMMatrix* AsMatrix() const final { return nullptr; }
   CSSFunctionValue* ToCSSValue() const final;
 
   DEFINE_INLINE_VIRTUAL_TRACE() {
     visitor->Trace(length_);
     CSSTransformComponent::Trace(visitor);
   }
 
  private:
-  CSSPerspective(CSSNumericValue* length) : length_(length) {}
+  CSSPerspective(CSSNumericValue* length)
+      : CSSTransformComponent(false /* is2D */), length_(length) {}
 
   Member<CSSNumericValue> length_;
 };
 
 }  // namespace blink
 
 #endif