Make CounterDirectiveMap a class and implement a Clone() method.

third_party/WebKit/Source/core/style/CounterDirectives.cpp

Index: third_party/WebKit/Source/core/style/CounterDirectives.cpp
diff --git a/third_party/WebKit/Source/core/style/CounterDirectives.cpp b/third_party/WebKit/Source/core/style/CounterDirectives.cpp
index 1203c5410af917ef13657ae241b480a687bc5cb9..f922b6bcf8754f5cfe456587d0f65081fa649c8d 100644
--- a/third_party/WebKit/Source/core/style/CounterDirectives.cpp
+++ b/third_party/WebKit/Source/core/style/CounterDirectives.cpp
@@ -32,12 +32,4 @@ bool operator==(const CounterDirectives& a, const CounterDirectives& b) {
          a.IsReset() == b.IsReset() && a.ResetValue() == b.ResetValue();
 }
 
-std::unique_ptr<CounterDirectiveMap> Clone(
-    const CounterDirectiveMap& counter_directives) {
-  std::unique_ptr<CounterDirectiveMap> result =
-      WTF::WrapUnique(new CounterDirectiveMap);
-  *result = counter_directives;
-  return result;
-}
-
 }  // namespace blink