Store retained object keys in all CPDF_DocPageData maps.

Then propagate changes to callers as necessary,

Change-Id: I8dc79f86e85e5015703ed3f1a4a49df219be5535
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/98235
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fpdfsdk/fpdf_editpage.cpp b/fpdfsdk/fpdf_editpage.cpp
index 8352117..c88ecfb 100644
--- a/fpdfsdk/fpdf_editpage.cpp
+++ b/fpdfsdk/fpdf_editpage.cpp
@@ -172,7 +172,7 @@
     }
   }
 
-  CPDF_Dictionary* pInfoDict = pDoc->GetInfo();
+  RetainPtr<CPDF_Dictionary> pInfoDict = pDoc->GetInfo();
   if (pInfoDict) {
     if (IsPDFSandboxPolicyEnabled(FPDF_POLICY_MACHINETIME_ACCESS))
       pInfoDict->SetNewFor<CPDF_String>("CreationDate", DateStr, false);