Revert "Remove OwnPtr from Blink."

third_party/WebKit/Source/core/animation/UnderlyingLengthChecker.h

 // Copyright 2015 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 UnderlyingLengthChecker_h
 #define UnderlyingLengthChecker_h
 
 #include "core/animation/InterpolableValue.h"
 #include "core/animation/InterpolationType.h"
-#include "wtf/PtrUtil.h"
-#include <memory>
 
 namespace blink {
 
 class UnderlyingLengthChecker : public InterpolationType::ConversionChecker {
 public:
-    static std::unique_ptr<UnderlyingLengthChecker> create(size_t underlyingLength)
+    static PassOwnPtr<UnderlyingLengthChecker> create(size_t underlyingLength)
     {
-        return wrapUnique(new UnderlyingLengthChecker(underlyingLength));
+        return adoptPtr(new UnderlyingLengthChecker(underlyingLength));
     }
 
     static size_t getUnderlyingLength(const InterpolationValue& underlying)
     {
         if (!underlying)
             return 0;
         return toInterpolableList(*underlying.interpolableValue).length();
     }
 
     bool isValid(const InterpolationEnvironment&, const InterpolationValue& underlying) const final
     {
         return m_underlyingLength == getUnderlyingLength(underlying);
     }
 
 private:
     UnderlyingLengthChecker(size_t underlyingLength)
         : m_underlyingLength(underlyingLength)
     {}
 
     size_t m_underlyingLength;
 };
 
 } // namespace blink
 
 #endif // UnderlyingLengthChecker_h