[CSS Typed OM] Add CSSValue->CSSSkew conversions

third_party/WebKit/Source/core/css/cssom/CSSSkew.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 CSSSkew_h
 #define CSSSkew_h
 
 #include "core/css/cssom/CSSAngleValue.h"
 #include "core/css/cssom/CSSMatrixTransformComponent.h"
 #include "core/css/cssom/CSSTransformComponent.h"
 
 namespace blink {
 
 class CORE_EXPORT CSSSkew final : public CSSTransformComponent {
   WTF_MAKE_NONCOPYABLE(CSSSkew);
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   static CSSSkew* create(const CSSAngleValue* ax, const CSSAngleValue* ay) {
     return new CSSSkew(ax, ay);
   }
 
-  static CSSSkew* fromCSSValue(const CSSFunctionValue& value) {
-    return nullptr;
-  }
+  static CSSSkew* fromCSSValue(const CSSFunctionValue&);
 
   // Bindings requires returning non-const pointers. This is safe because
   // CSSAngleValues are immutable.
   CSSAngleValue* ax() const { return const_cast<CSSAngleValue*>(m_ax.get()); }
   CSSAngleValue* ay() const { return const_cast<CSSAngleValue*>(m_ay.get()); }
 
   TransformComponentType type() const override { return SkewType; }
 
   CSSMatrixTransformComponent* asMatrix() const override {
     return CSSMatrixTransformComponent::skew(m_ax->degrees(), m_ay->degrees());
@@ skipping 11 matching lines @@
   CSSSkew(const CSSAngleValue* ax, const CSSAngleValue* ay)
       : CSSTransformComponent(), m_ax(ax), m_ay(ay) {}
 
   Member<const CSSAngleValue> m_ax;
   Member<const CSSAngleValue> m_ay;
 };
 
 }  // namespace blink
 
 #endif