Replace SmartPointer<T> with unique_ptr<T>

src/string-stream.h

 // Copyright 2014 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_STRING_STREAM_H_
 #define V8_STRING_STREAM_H_
 
 #include <memory>
 
 #include "src/allocation.h"
-#include "src/base/smart-pointers.h"
 #include "src/handles.h"
 #include "src/vector.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class ByteArray;
 
 class StringAllocator {
@@ skipping 155 matching lines @@
   bool full() const { return (capacity_ - length_) == 1; }
   int space() const { return capacity_ - length_; }
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(StringStream);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_STRING_STREAM_H_