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

core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp

Index: core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index 02ac27ac0fca87b9a596ea68f614118c14fbc05f..1c4cc24208f70579e0d5fe8b4d9b613bb1220a7a 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -92,7 +92,7 @@ void CPDF_StreamContentParser::Handle_BeginImage() {
     }
     CFX_ByteString key((const FX_CHAR*)m_pSyntax->GetWordBuf() + 1,
                        m_pSyntax->GetWordSize() - 1);
-    nonstd::unique_ptr<CPDF_Object, ReleaseDeleter<CPDF_Object>> pObj(
+    std::unique_ptr<CPDF_Object, ReleaseDeleter<CPDF_Object>> pObj(
         m_pSyntax->ReadNextObject());
     if (!key.IsEmpty()) {
       FX_DWORD dwObjNum = pObj ? pObj->GetObjNum() : 0;