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

third_party/WebKit/Source/core/css/cssom/CSSTransformValue.cpp

 // 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.
 
 #include "core/css/cssom/CSSTransformValue.h"
 
 #include "core/css/CSSValueList.h"
+#include "core/css/cssom/CSSMatrixComponent.h"
 #include "core/css/cssom/CSSTransformComponent.h"
+#include "core/geometry/DOMMatrix.h"
 
 namespace blink {
 
 CSSTransformValue* CSSTransformValue::FromCSSValue(const CSSValue& css_value) {
   if (!css_value.IsValueList()) {
     // TODO(meade): Also need to check the separator here if we care.
     return nullptr;
   }
   HeapVector<Member<CSSTransformComponent>> components;
   for (const CSSValue* value : ToCSSValueList(css_value)) {
     CSSTransformComponent* component =
         CSSTransformComponent::FromCSSValue(*value);
     if (!component)
       return nullptr;
     components.push_back(component);
   }
   return CSSTransformValue::Create(components);
 }
 
 bool CSSTransformValue::is2D() const {
   for (size_t i = 0; i < transform_components_.size(); i++) {
     if (!transform_components_[i]->is2D()) {
       return false;
     }
   }
   return true;
 }
 
+DOMMatrix* CSSTransformValue::toMatrix() const {
+  DOMMatrix* matrix = DOMMatrix::Create();
+  for (size_t i = 0; i < transform_components_.size(); i++) {
+    CSSMatrixComponent* matrixComponent = transform_components_[i]->asMatrix();
+    if (matrixComponent) {
+      matrix->multiplySelf(matrixComponent->matrix());
+    }
+  }
+  return matrix;
+}
+
 const CSSValue* CSSTransformValue::ToCSSValue() const {
   CSSValueList* transform_css_value = CSSValueList::CreateSpaceSeparated();
   for (size_t i = 0; i < transform_components_.size(); i++) {
     const CSSValue* component = transform_components_[i]->ToCSSValue();
     // TODO(meade): Remove this check once numbers and lengths are rewritten.
     if (!component)
       return nullptr;
     transform_css_value->Append(*component);
   }
   return transform_css_value;
 }
 
 }  // namespace blink