Merge V8 5.2.361.47  DO NOT MERGE

https://chromium.googlesource.com/v8/v8/+/5.2.361.47

FPIIM-449

Change-Id: Ibec421b85a9b88cb3a432ada642e469fe7e78346
(cherry picked from commit bcf72ee8e3b26f1d0726869c7ddb3921c68b09a8)
diff --git a/src/compiler/simplified-operator-reducer.h b/src/compiler/simplified-operator-reducer.h
index 13301c2..70750a8 100644
--- a/src/compiler/simplified-operator-reducer.h
+++ b/src/compiler/simplified-operator-reducer.h
@@ -30,6 +30,7 @@
 
  private:
   Reduction ReduceReferenceEqual(Node* node);
+  Reduction ReduceTypeGuard(Node* node);
 
   Reduction Change(Node* node, const Operator* op, Node* a);
   Reduction ReplaceFloat64(double value);