Split CPDF_PageObjectHolder off from CPDF_PageObjectList

Eventually, we're going to expose an iterator over
CPDF_PageObjectList that we don't want to be inherited by
the CPDF_PageObjectHolder sub-classes: page and form.

Also, the operations that the object holder performs dealing
with inquiring about masks and such seem beyond the scope of
what a list would provide.  Hence the "Holder" name.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1701073002 .

1 files changed, 3 insertions, 2 deletions

diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index 413b391eee..36b8319dca 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -42,9 +42,10 @@ FX_BOOL GetContentsRect(CPDF_Document* pDoc,
   pPDFPage->Load(pDoc, pDict, FALSE);
   pPDFPage->ParseContent(nullptr);
 
-  FX_POSITION pos = pPDFPage->GetFirstObjectPosition();
+  FX_POSITION pos = pPDFPage->GetPageObjectList()->GetHeadPosition();
   while (pos) {
-    CPDF_PageObject* pPageObject = pPDFPage->GetNextObject(pos);
+    CPDF_PageObject* pPageObject =
+        pPDFPage->GetPageObjectList()->GetNextObject(pos);
     if (!pPageObject)
       continue;