Make RareNonInheritedData use MemberCopy and DataEquivalent.

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

Index: third_party/WebKit/Source/core/style/MemberCopy.h
diff --git a/third_party/WebKit/Source/core/style/MemberCopy.h b/third_party/WebKit/Source/core/style/MemberCopy.h
index 93631e8109743eb38fe64c4a4fe431ed3c8db519..4fef934f9171108001a020e89bd0c7a1216bdf37 100644
--- a/third_party/WebKit/Source/core/style/MemberCopy.h
+++ b/third_party/WebKit/Source/core/style/MemberCopy.h
@@ -5,6 +5,10 @@
 #ifndef MemberCopy_h
 #define MemberCopy_h
 
+#include <memory>
+#include "core/style/ContentData.h"
+#include "core/style/DataPersistent.h"
+#include "core/style/DataRef.h"
 #include "platform/heap/Persistent.h"
 #include "platform/wtf/RefPtr.h"
 
@@ -20,6 +24,27 @@ Persistent<T> MemberCopy(const Persistent<T>& v) {
   return v;
 }
 
+template <typename T>
+std::unique_ptr<T> MemberCopy(const std::unique_ptr<T>& v) {
+  return v ? v->Clone() : nullptr;
+}
+
+template <typename T>
+DataPersistent<T> MemberCopy(const DataPersistent<T>& v) {
+  return v;
+}
+
+// TODO(shend): Remove this once all subgroups of StyleRareNonInheritedData are
+// generated
+template <typename T>
+DataRef<T> MemberCopy(const DataRef<T>& v) {
+  return v;
+}
+
+inline Persistent<ContentData> MemberCopy(const Persistent<ContentData>& v) {
+  return v ? v->Clone() : nullptr;
+}
+
 }  // namespace blink
 
 #endif  // MemberCopy_h