[LayoutNG] Switch NGBreakToken to being RefCounted.

third_party/WebKit/Source/core/layout/ng/ng_break_token.h

Index: third_party/WebKit/Source/core/layout/ng/ng_break_token.h
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_break_token.h b/third_party/WebKit/Source/core/layout/ng/ng_break_token.h
index 94fb6d19a6e7a226557f3ef0ff6e94878dc2bd4d..d055ba4179de9fd8e2abd0d6ed243ae97e989a53 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_break_token.h
+++ b/third_party/WebKit/Source/core/layout/ng/ng_break_token.h
@@ -6,12 +6,12 @@
 #define NGBreakToken_h
 
 #include "core/CoreExport.h"
+#include "core/layout/ng/ng_layout_input_node.h"
 #include "platform/heap/Handle.h"
+#include "wtf/RefCounted.h"
 
 namespace blink {
 
-class NGLayoutInputNode;
-
 // A break token is a continuation token for layout. A single layout input node
 // can have multiple fragments asssociated with it.
 //
@@ -31,8 +31,7 @@ class NGLayoutInputNode;
 // NGPhysicalFragment* fragment2 = node->Layout(space, fragment->BreakToken());
 //
 // The break token should encapsulate enough information to "resume" the layout.
-class CORE_EXPORT NGBreakToken
-    : public GarbageCollectedFinalized<NGBreakToken> {
+class CORE_EXPORT NGBreakToken : public RefCounted<NGBreakToken> {
  public:
   virtual ~NGBreakToken() {}
 
@@ -48,8 +47,6 @@ class CORE_EXPORT NGBreakToken
   // used with any other node.
   NGLayoutInputNode* InputNode() const { return node_; }
 
-  DEFINE_INLINE_VIRTUAL_TRACE() { visitor->trace(node_); }
-
  protected:
   NGBreakToken(NGBreakTokenType type,
                NGBreakTokenStatus status,
@@ -60,7 +57,7 @@ class CORE_EXPORT NGBreakToken
   unsigned type_ : 1;
   unsigned status_ : 1;
 
-  Member<NGLayoutInputNode> node_;
+  Persistent<NGLayoutInputNode> node_;
 };
 
 }  // namespace blink