[turbofan] Cleanup use of virtual, OVERRIDE, FINAL.

src/compiler/js-generic-lowering.h

Index: src/compiler/js-generic-lowering.h
diff --git a/src/compiler/js-generic-lowering.h b/src/compiler/js-generic-lowering.h
index eb234b84ff3a94fa27b5aa4c4b9255cd4ed3bc27..f6263385edca6a938034fe7f36b0e479d171a10e 100644
--- a/src/compiler/js-generic-lowering.h
+++ b/src/compiler/js-generic-lowering.h
@@ -22,13 +22,14 @@ class CommonOperatorBuilder;
 class MachineOperatorBuilder;
 class Linkage;
 
+
 // Lowers JS-level operators to runtime and IC calls in the "generic" case.
-class JSGenericLowering : public Reducer {
+class JSGenericLowering FINAL : public Reducer {
  public:
   JSGenericLowering(CompilationInfo* info, JSGraph* graph);
-  virtual ~JSGenericLowering() {}
+  ~JSGenericLowering() FINAL {}
 
-  virtual Reduction Reduce(Node* node);
+  Reduction Reduce(Node* node) FINAL;
 
  protected:
 #define DECLARE_LOWER(x) void Lower##x(Node* node);