Implement CPDF_Object::MakeReference method.

Change-Id: I153747ef587a184eaef58ff09dbf8f214c9ddfb3
Reviewed-on: https://pdfium-review.googlesource.com/17230
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Art Snake <art-snake@yandex-team.ru>

core/fpdfapi/page/cpdf_image.cpp

diff --git a/core/fpdfapi/page/cpdf_image.cpp b/core/fpdfapi/page/cpdf_image.cpp
index 8720342..a8b5936 100644
--- a/core/fpdfapi/page/cpdf_image.cpp
+++ b/core/fpdfapi/page/cpdf_image.cpp
@@ -238,9 +238,8 @@
           pdfium::MakeUnique<CPDF_Dictionary>(m_pDocument->GetByteStringPool());
       CPDF_Stream* pCTS = m_pDocument->NewIndirect<CPDF_Stream>(
           std::move(pColorTable), iPalette * 3, std::move(pNewDict));
-      pCS->AddNew<CPDF_Reference>(m_pDocument.Get(), pCTS->GetObjNum());
-      pDict->SetNewFor<CPDF_Reference>("ColorSpace", m_pDocument.Get(),
-                                       pCS->GetObjNum());
+      pCS->Add(pCTS->MakeReference(m_pDocument.Get()));
+      pDict->SetFor("ColorSpace", pCS->MakeReference(m_pDocument.Get()));
     } else {
       pDict->SetNewFor<CPDF_Name>("ColorSpace", "DeviceGray");
     }
@@ -281,8 +280,7 @@
     pMaskDict->SetNewFor<CPDF_Number>("Length", mask_size);
     CPDF_Stream* pNewStream = m_pDocument->NewIndirect<CPDF_Stream>(
         std::move(mask_buf), mask_size, std::move(pMaskDict));
-    pDict->SetNewFor<CPDF_Reference>("SMask", m_pDocument.Get(),
-                                     pNewStream->GetObjNum());
+    pDict->SetFor("SMask", pNewStream->MakeReference(m_pDocument.Get()));
   }
 
   uint8_t* src_buf = pBitmap->GetBuffer();