Remove SynchronousMode, as it is always ForceSynchronous.

Source/core/html/parser/HTMLDocumentParser.h

Index: Source/core/html/parser/HTMLDocumentParser.h
diff --git a/Source/core/html/parser/HTMLDocumentParser.h b/Source/core/html/parser/HTMLDocumentParser.h
index a7c379ef8cfb806bb5a03dfdcb125684c5018952..5164805910b5459cc6f40d131c618c584f353c7e 100644
--- a/Source/core/html/parser/HTMLDocumentParser.h
+++ b/Source/core/html/parser/HTMLDocumentParser.h
@@ -150,13 +150,9 @@ private:
 
     Document* contextForParsingSession();
 
-    enum SynchronousMode {
-        AllowYield,
-        ForceSynchronous,
-    };
-    bool canTakeNextToken(SynchronousMode, PumpSession&);
-    void pumpTokenizer(SynchronousMode);
-    void pumpTokenizerIfPossible(SynchronousMode);
+    bool canTakeNextToken(PumpSession&);
+    void pumpTokenizer();
+    void pumpTokenizerIfPossible();
     void constructTreeFromHTMLToken(HTMLToken&);
     void constructTreeFromCompactHTMLToken(const CompactHTMLToken&);