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

fpdfsdk/src/javascript/JS_Runtime_Stub.cpp

 // Copyright 2015 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
 
+#include <memory>
+
 #include "fpdfsdk/include/fsdk_mgr.h"  // For CPDFDoc_Environment.
 #include "fpdfsdk/include/javascript/IJavaScript.h"
-#include "third_party/base/nonstd_unique_ptr.h"
 
 class CJS_ContextStub final : public IJS_Context {
  public:
   CJS_ContextStub() {}
   ~CJS_ContextStub() override {}
 
   // IJS_Context:
   FX_BOOL RunScript(const CFX_WideString& script,
                     CFX_WideString* info) override {
     return FALSE;
@@ skipping 117 matching lines @@
   CPDFSDK_Document* GetReaderDocument() override { return m_pDoc; }
 
   int Execute(IJS_Context* cc,
               const wchar_t* script,
               CFX_WideString* info) override {
     return 0;
   }
 
  protected:
   CPDFSDK_Document* m_pDoc;
-  nonstd::unique_ptr<CJS_ContextStub> m_pContext;
+  std::unique_ptr<CJS_ContextStub> m_pContext;
 };
 
 // static
 void IJS_Runtime::Initialize(unsigned int slot, void* isolate) {
 }
 
 // static
 IJS_Runtime* IJS_Runtime::Create(CPDFDoc_Environment* pEnv) {
   return new CJS_RuntimeStub;
 }