Remove unused methods in HTMLTokenizer

Source/core/html/parser/HTMLTokenizer.h

Index: Source/core/html/parser/HTMLTokenizer.h
diff --git a/Source/core/html/parser/HTMLTokenizer.h b/Source/core/html/parser/HTMLTokenizer.h
index 494e20c3affcb60d79b537726db52558a7f5ad9e..f6097c330d4274f3cc07a1bfe3d8545c1fbb0c23 100644
--- a/Source/core/html/parser/HTMLTokenizer.h
+++ b/Source/core/html/parser/HTMLTokenizer.h
@@ -139,10 +139,6 @@ public:
         }
     };
 
-    bool canCreateCheckpoint() const;
-    void createCheckpoint(Checkpoint&) const;
-    void restoreFromCheckpoint(const Checkpoint&);
-
     // This function returns true if it emits a token. Otherwise, callers
     // must provide the same (in progress) token on the next call (unless
     // they call reset() first).