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

core/src/fpdfapi/fpdf_font/fpdf_font.cpp

Index: core/src/fpdfapi/fpdf_font/fpdf_font.cpp
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
index a3de6f2777ab1feb202876af23d63e6b63c2d762..003825b898b2f63184a93b2f249b57106c733568 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font.cpp
@@ -1700,7 +1700,7 @@ CPDF_Type3Char* CPDF_Type3Font::LoadChar(FX_DWORD charcode, int level) {
   if (!pStream)
     return nullptr;
 
-  nonstd::unique_ptr<CPDF_Type3Char> pNewChar(new CPDF_Type3Char(new CPDF_Form(
+  std::unique_ptr<CPDF_Type3Char> pNewChar(new CPDF_Type3Char(new CPDF_Form(
       m_pDocument, m_pFontResources ? m_pFontResources : m_pPageResources,
       pStream, nullptr)));