[regexp] remove some dead code.

src/regexp/regexp-macro-assembler-tracer.h

Index: src/regexp/regexp-macro-assembler-tracer.h
diff --git a/src/regexp/regexp-macro-assembler-tracer.h b/src/regexp/regexp-macro-assembler-tracer.h
index 3a94ee80bdb601422111091adb303c72e92d423c..77377aac314774d202b8912750467290ced0cda5 100644
--- a/src/regexp/regexp-macro-assembler-tracer.h
+++ b/src/regexp/regexp-macro-assembler-tracer.h
@@ -51,6 +51,7 @@ class RegExpMacroAssemblerTracer: public RegExpMacroAssembler {
                                         uc16 to,
                                         Label* on_not_in_range);
   virtual void CheckBitInTable(Handle<ByteArray> table, Label* on_bit_set);
+  virtual void CheckPosition(int cp_offset, Label* on_outside_input);
   virtual bool CheckSpecialCharacterClass(uc16 type,
                                           Label* on_no_match);
   virtual void Fail();