[LayoutNG] Initial support for multicol, introducing NGBlockBreakToken.

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 2ddb11124c0d5695d3919a8c2d4445cb1a52f17c..7a1778fbdd19448090df0b0e8091f0b4c041c180 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
@@ -13,10 +13,20 @@ namespace blink {
 class CORE_EXPORT NGBreakToken
     : public GarbageCollectedFinalized<NGBreakToken> {
  public:
-  NGBreakToken() {}
+  virtual ~NGBreakToken() {}
 
-  DEFINE_INLINE_TRACE() {}
+  enum NGBreakTokenType { kBlockBreakToken, kTextBreakToken };
+  NGBreakTokenType Type() const { return static_cast<NGBreakTokenType>(type_); }
+
+  DEFINE_INLINE_VIRTUAL_TRACE() {}
+
+ protected:
+  NGBreakToken(NGBreakTokenType type) : type_(type) {}
+
+ private:
+  unsigned type_ : 1;
 };
-}
 
-#endif
+}  // namespace blink
+
+#endif  // NGBreakToken_h