Switch from nonstd::unique_ptr to std::unique_ptr.

core/src/fxcodec/jbig2/JBig2_SymbolDict.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_SRC_FXCODEC_JBIG2_JBIG2_SYMBOLDICT_H_
 #define CORE_SRC_FXCODEC_JBIG2_JBIG2_SYMBOLDICT_H_
 
+#include <memory>
 #include <vector>
 
 #include "JBig2_ArithDecoder.h"
 #include "JBig2_List.h"
 #include "core/include/fxcrt/fx_basic.h"
-#include "third_party/base/nonstd_unique_ptr.h"
 
 class CJBig2_Image;
 
 class CJBig2_SymbolDict {
  public:
   CJBig2_SymbolDict();
   ~CJBig2_SymbolDict();
 
-  nonstd::unique_ptr<CJBig2_SymbolDict> DeepCopy() const;
+  std::unique_ptr<CJBig2_SymbolDict> DeepCopy() const;
 
   // Takes ownership of |image|.
   void AddImage(CJBig2_Image* image) { m_SDEXSYMS.push_back(image); }
 
   size_t NumImages() const { return m_SDEXSYMS.size(); }
   CJBig2_Image* GetImage(size_t index) const { return m_SDEXSYMS.get(index); }
 
   const std::vector<JBig2ArithCtx>& GbContext() const { return m_gbContext; }
   const std::vector<JBig2ArithCtx>& GrContext() const { return m_grContext; }
 
   void SetGbContext(const std::vector<JBig2ArithCtx>& gbContext) {
     m_gbContext = gbContext;
   }
   void SetGrContext(const std::vector<JBig2ArithCtx>& grContext) {
     m_grContext = grContext;
   }
 
  private:
   std::vector<JBig2ArithCtx> m_gbContext;
   std::vector<JBig2ArithCtx> m_grContext;
   CJBig2_List<CJBig2_Image> m_SDEXSYMS;
 };
 
 #endif  // CORE_SRC_FXCODEC_JBIG2_JBIG2_SYMBOLDICT_H_