Replace SmartPointer<T> with unique_ptr<T>

src/s390/codegen-s390.cc

Index: src/s390/codegen-s390.cc
diff --git a/src/s390/codegen-s390.cc b/src/s390/codegen-s390.cc
index 5728e459b9ee8957fee7b075b8f78afda93035f4..d92cc54ab2e7c674900388f4e8a02d86584e9cf3 100644
--- a/src/s390/codegen-s390.cc
+++ b/src/s390/codegen-s390.cc
@@ -6,6 +6,8 @@
 
 #if V8_TARGET_ARCH_S390
 
+#include <memory>
+
 #include "src/codegen.h"
 #include "src/macro-assembler.h"
 #include "src/s390/simulator-s390.h"
@@ -466,7 +468,7 @@ CodeAgingHelper::CodeAgingHelper(Isolate* isolate) {
   // to avoid overloading the stack in stress conditions.
   // DONT_FLUSH is used because the CodeAgingHelper is initialized early in
   // the process, before ARM simulator ICache is setup.
-  base::SmartPointer<CodePatcher> patcher(
+  std::unique_ptr<CodePatcher> patcher(
       new CodePatcher(isolate, young_sequence_.start(),
                       young_sequence_.length(), CodePatcher::DONT_FLUSH));
   PredictableCodeSizeScope scope(patcher->masm(), young_sequence_.length());