Add type cast definitions for CPDF_Reference.

This Cl adds ToReference, CPDF_Object::AsReference and CPDF_Object::IsReference
and updates the src to use them as needed.

BUG=pdfium:201
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1420973002 .

3 files changed, 5 insertions, 9 deletions

diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index 39441c4aef..75db8f806d 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -444,12 +444,10 @@ DLLEXPORT int STDCALL FPDFPage_Flatten(FPDF_PAGE page, int nFlag) {
           CFX_ByteString sKey;
           CPDF_Object* pFirstObj = pAPDic->GetNextElement(pos, sKey);
           if (pFirstObj) {
-            if (pFirstObj->GetType() == PDFOBJ_REFERENCE)
+            if (pFirstObj->IsReference())
               pFirstObj = pFirstObj->GetDirect();
-
             if (!pFirstObj->IsStream())
               continue;
-
             pAPStream = pFirstObj->AsStream();
           }
         }
diff --git a/fpdfsdk/src/fpdf_transformpage.cpp b/fpdfsdk/src/fpdf_transformpage.cpp
index 20713fe07d..8a835fb220 100644
--- a/fpdfsdk/src/fpdf_transformpage.cpp
+++ b/fpdfsdk/src/fpdf_transformpage.cpp
@@ -135,8 +135,7 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFPage_TransFormWithClip(FPDF_PAGE page,
     CPDF_Reference* pRef = new CPDF_Reference(pDoc, pStream->GetObjNum());
     pContentArray->InsertAt(0, pRef);
     pContentArray->AddReference(pDoc, pEndStream);
-  } else if (pContentObj && pContentObj->GetType() == PDFOBJ_REFERENCE) {
-    CPDF_Reference* pReference = (CPDF_Reference*)pContentObj;
+  } else if (CPDF_Reference* pReference = ToReference(pContentObj)) {
     CPDF_Object* pDirectObj = pReference->GetDirect();
     if (pDirectObj) {
       if (CPDF_Array* pArray = pDirectObj->AsArray()) {
@@ -165,7 +164,7 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFPage_TransFormWithClip(FPDF_PAGE page,
         CPDF_Dictionary* pDict = nullptr;
         CFX_ByteString key;
         CPDF_Object* pObj = pPattenDict->GetNextElement(pos, key);
-        if (pObj->GetType() == PDFOBJ_REFERENCE)
+        if (pObj->IsReference())
           pObj = pObj->GetDirect();
 
         if (pObj->IsDictionary())
@@ -306,8 +305,7 @@ DLLEXPORT void STDCALL FPDFPage_InsertClipPath(FPDF_PAGE page,
     pContentArray = pArray;
     CPDF_Reference* pRef = new CPDF_Reference(pDoc, pStream->GetObjNum());
     pContentArray->InsertAt(0, pRef);
-  } else if (pContentObj && pContentObj->GetType() == PDFOBJ_REFERENCE) {
-    CPDF_Reference* pReference = (CPDF_Reference*)pContentObj;
+  } else if (CPDF_Reference* pReference = ToReference(pContentObj)) {
     CPDF_Object* pDirectObj = pReference->GetDirect();
     if (pDirectObj) {
       if (CPDF_Array* pArray = pDirectObj->AsArray()) {
diff --git a/fpdfsdk/src/fpdfppo.cpp b/fpdfsdk/src/fpdfppo.cpp
index c9df813789..6bdd7c5e67 100644
--- a/fpdfsdk/src/fpdfppo.cpp
+++ b/fpdfsdk/src/fpdfppo.cpp
@@ -207,7 +207,7 @@ FX_BOOL CPDF_PageOrganizer::UpdateReference(CPDF_Object* pObj,
                                             ObjectNumberMap* pObjNumberMap) {
   switch (pObj->GetType()) {
     case PDFOBJ_REFERENCE: {
-      CPDF_Reference* pReference = (CPDF_Reference*)pObj;
+      CPDF_Reference* pReference = pObj->AsReference();
       FX_DWORD newobjnum = GetNewObjId(pDoc, pObjNumberMap, pReference);
       if (newobjnum == 0)
         return FALSE;