Make CPDF_Object subclass constructors intern strings

fpdfsdk/fpdfeditpage.cpp

Index: fpdfsdk/fpdfeditpage.cpp
diff --git a/fpdfsdk/fpdfeditpage.cpp b/fpdfsdk/fpdfeditpage.cpp
index 9dc8ae9099b0b89bc99589782b4c38a2f00b7093..847adac7eceb48ae4aa3c5b21c996345110581dd 100644
--- a/fpdfsdk/fpdfeditpage.cpp
+++ b/fpdfsdk/fpdfeditpage.cpp
@@ -83,8 +83,10 @@ DLLEXPORT FPDF_DOCUMENT STDCALL FPDF_CreateNewDocument() {
   CPDF_Dictionary* pInfoDict = nullptr;
   pInfoDict = pDoc->GetInfo();
   if (pInfoDict) {
-    if (FSDK_IsSandBoxPolicyEnabled(FPDF_POLICY_MACHINETIME_ACCESS))
-      pInfoDict->SetFor("CreationDate", new CPDF_String(DateStr, false));
+    if (FSDK_IsSandBoxPolicyEnabled(FPDF_POLICY_MACHINETIME_ACCESS)) {
+      pInfoDict->SetFor("CreationDate",
+                        new CPDF_String(nullptr, DateStr, false));
+    }
     pInfoDict->SetFor("Creator", new CPDF_String(L"PDFium"));
   }