Make NinePieceImageData use RefCountedCopyable.

third_party/WebKit/Source/core/style/NinePieceImage.h

Index: third_party/WebKit/Source/core/style/NinePieceImage.h
diff --git a/third_party/WebKit/Source/core/style/NinePieceImage.h b/third_party/WebKit/Source/core/style/NinePieceImage.h
index 9a3e14c503dcfdc69f745e0ecb2c34f747573ae4..18d50861b86877d7c3cf410b122e7c7bbe5fc610 100644
--- a/third_party/WebKit/Source/core/style/NinePieceImage.h
+++ b/third_party/WebKit/Source/core/style/NinePieceImage.h
@@ -43,7 +43,8 @@ enum ENinePieceImageRule {
   kRepeatImageRule
 };
 
-class CORE_EXPORT NinePieceImageData : public RefCounted<NinePieceImageData> {
+class CORE_EXPORT NinePieceImageData
+    : public RefCountedCopyable<NinePieceImageData> {
  public:
   static PassRefPtr<NinePieceImageData> Create() {
     return AdoptRef(new NinePieceImageData);
@@ -65,7 +66,7 @@ class CORE_EXPORT NinePieceImageData : public RefCounted<NinePieceImageData> {
 
  private:
   NinePieceImageData();
-  NinePieceImageData(const NinePieceImageData&);
+  NinePieceImageData(const NinePieceImageData&) = default;
 };
 
 class CORE_EXPORT NinePieceImage {