Return retained references from CPDF_PageObjectHolder methods.

Propagate these into a few called methods.

-- fix some local names while at it.

Change-Id: Ib03a04672baf7a63cfdc8b33370c16f8a5cc7200
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/99010
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 2d6ff76..fbc059b 100644
--- a/fpdfsdk/fpdf_editpage.cpp
+++ b/fpdfsdk/fpdf_editpage.cpp
@@ -67,7 +67,7 @@
   if (!pPage)
     return false;
 
-  const CPDF_Dictionary* pFormDict = pPage->GetDict();
+  RetainPtr<const CPDF_Dictionary> pFormDict = pPage->GetDict();
   if (!pFormDict->KeyExist(pdfium::page_object::kType))
     return false;