[compiler] Delete unused variable.

src/compiler/loop-variable-optimizer.h

Index: src/compiler/loop-variable-optimizer.h
diff --git a/src/compiler/loop-variable-optimizer.h b/src/compiler/loop-variable-optimizer.h
index 261d9650daf1947be22d0078ad535a3855f24c52..c7e82dc6f5bd8e85bc87012cfa9a04a225130f64 100644
--- a/src/compiler/loop-variable-optimizer.h
+++ b/src/compiler/loop-variable-optimizer.h
@@ -45,8 +45,8 @@ class InductionVariable : public ZoneObject {
         lower_bounds_(zone),
         upper_bounds_(zone) {}
 
-  void AddUpperBound(Node* bound, ConstraintKind kind, Zone* graph_zone);
-  void AddLowerBound(Node* bound, ConstraintKind kind, Zone* graph_zone);
+  void AddUpperBound(Node* bound, ConstraintKind kind);
+  void AddLowerBound(Node* bound, ConstraintKind kind);
 
   Node* phi_;
   Node* arith_;