[turbofan] Stub for typeof operator.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 14c9a65ee0ccf8a752c9dda4f49b1c68da5db8da..0a55e16797d374d540fbe0e7e0856253f4a2b078 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -1057,15 +1057,12 @@ class NumberToStringStub final : public HydrogenCodeStub {
   DEFINE_HYDROGEN_CODE_STUB(NumberToString, HydrogenCodeStub);
 };
 
-
-class TypeofStub final : public HydrogenCodeStub {
+class TypeofStub final : public TurboFanCodeStub {
  public:
-  explicit TypeofStub(Isolate* isolate) : HydrogenCodeStub(isolate) {}
-
-  static void GenerateAheadOfTime(Isolate* isolate);
+  explicit TypeofStub(Isolate* isolate) : TurboFanCodeStub(isolate) {}
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(Typeof);
-  DEFINE_HYDROGEN_CODE_STUB(Typeof, HydrogenCodeStub);
+  DEFINE_TURBOFAN_UNARY_OP_CODE_STUB(Typeof, TurboFanCodeStub);
 };
 
 class FastNewClosureStub : public TurboFanCodeStub {