Replace SmartPointer<T> with unique_ptr<T>

src/wasm/decoder.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_WASM_DECODER_H_
 #define V8_WASM_DECODER_H_
 
 #include <memory>
 
 #include "src/base/compiler-specific.h"
-#include "src/base/smart-pointers.h"
 #include "src/flags.h"
 #include "src/signature.h"
 #include "src/utils.h"
 #include "src/wasm/wasm-result.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
@@ skipping 350 matching lines @@
     return result;
   }
 };
 
 #undef TRACE
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_DECODER_H_