Add ptr_util.h from base until std::make_unique<> available

core/fxge/ge/cfx_fontmgr.cpp

Index: core/fxge/ge/cfx_fontmgr.cpp
diff --git a/core/fxge/ge/cfx_fontmgr.cpp b/core/fxge/ge/cfx_fontmgr.cpp
index 54000e6b5dac418995bf96b2b65c0b6036a62112..95a2b662ed17ffa0eb2ef2f67fb2c05f9a5014ad 100644
--- a/core/fxge/ge/cfx_fontmgr.cpp
+++ b/core/fxge/ge/cfx_fontmgr.cpp
@@ -12,6 +12,7 @@
 #include "core/fxge/fx_font.h"
 #include "core/fxge/ge/cttfontdesc.h"
 #include "core/fxge/ifx_systemfontinfo.h"
+#include "third_party/base/ptr_util.h"
 
 namespace {
 
@@ -81,7 +82,7 @@ int GetTTCIndex(const uint8_t* pFontData,
 
 CFX_FontMgr::CFX_FontMgr()
     : m_FTLibrary(nullptr), m_FTLibrarySupportsHinting(false) {
-  m_pBuiltinMapper = WrapUnique(new CFX_FontMapper(this));
+  m_pBuiltinMapper = pdfium::MakeUnique<CFX_FontMapper>(this);
 }
 
 CFX_FontMgr::~CFX_FontMgr() {