Replace SmartPointer<T> with unique_ptr<T>

src/fast-accessor-assembler.h

Index: src/fast-accessor-assembler.h
diff --git a/src/fast-accessor-assembler.h b/src/fast-accessor-assembler.h
index 346592ea43382876e455ae3db49fcc1e149731b3..41337a2b09d8883efd2243e785040da4db4bfde3 100644
--- a/src/fast-accessor-assembler.h
+++ b/src/fast-accessor-assembler.h
@@ -6,11 +6,11 @@
 #define V8_FAST_ACCESSOR_ASSEMBLER_H_
 
 #include <stdint.h>
+#include <memory>
 #include <vector>
 
 #include "include/v8-experimental.h"
 #include "src/base/macros.h"
-#include "src/base/smart-pointers.h"
 #include "src/handles.h"
 
 // For CodeStubAssembler::Label. (We cannot forward-declare inner classes.)
@@ -83,7 +83,7 @@ class FastAccessorAssembler {
 
   Zone zone_;
   Isolate* isolate_;
-  base::SmartPointer<CodeStubAssembler> assembler_;
+  std::unique_ptr<CodeStubAssembler> assembler_;
 
   // To prevent exposing the RMA internals to the outside world, we'll map
   // Node + Label pointers integers wrapped in ValueId and LabelId instances.