[css-typed-om] add toMatrix() method in CSSTransformValue.idl

third_party/WebKit/Source/core/css/cssom/CSSTransformValue.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 CSSTransformValue_h
 #define CSSTransformValue_h
 
 #include "core/CoreExport.h"
 #include "core/css/cssom/CSSStyleValue.h"
 #include "core/css/cssom/CSSTransformComponent.h"
 #include "platform/bindings/ScriptWrappable.h"
 #include "platform/heap/HeapAllocator.h"
 
 namespace blink {
 
+class DOMMatrix;
+
 class CORE_EXPORT CSSTransformValue final : public CSSStyleValue {
   WTF_MAKE_NONCOPYABLE(CSSTransformValue);
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   static CSSTransformValue* Create() { return new CSSTransformValue(); }
 
   static CSSTransformValue* Create(
       const HeapVector<Member<CSSTransformComponent>>& transform_components) {
     return new CSSTransformValue(transform_components);
   }
 
   static CSSTransformValue* FromCSSValue(const CSSValue&);
 
   bool is2D() const;
 
+  DOMMatrix* toMatrix() const;
+
   const CSSValue* ToCSSValue() const override;
 
   StyleValueType GetType() const override { return kTransformType; }
 
   CSSTransformComponent* componentAtIndex(uint32_t index) {
     return transform_components_.at(index);
   }
 
   size_t length() const { return transform_components_.size(); }
 
   DEFINE_INLINE_VIRTUAL_TRACE() {
     visitor->Trace(transform_components_);
     CSSStyleValue::Trace(visitor);
   }
 
  private:
   CSSTransformValue() {}
   CSSTransformValue(
       const HeapVector<Member<CSSTransformComponent>>& transform_components)
       : CSSStyleValue(), transform_components_(transform_components) {}
 
   HeapVector<Member<CSSTransformComponent>> transform_components_;
 };
 
 }  // namespace blink
 
 #endif  // CSSTransformValue_h