Revert "Revert "Add type cast definitions for CPDF_Reference.""

This reverts commit 7e155865c90cc1115cc7193b7646a341d8f9093e.

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/1418923005 .

2 files changed, 17 insertions, 20 deletions

diff --git a/core/src/fpdfdoc/doc_form.cpp b/core/src/fpdfdoc/doc_form.cpp
index 8078608883..3192445d90 100644
--- a/core/src/fpdfdoc/doc_form.cpp
+++ b/core/src/fpdfdoc/doc_form.cpp
@@ -1086,13 +1086,12 @@ CPDF_FormField* CPDF_InterForm::AddTerminalField(CPDF_Dictionary* pFieldDict) {
     }
     pField = new CPDF_FormField(this, pParent);
     CPDF_Object* pTObj = pDict->GetElement("T");
-    if (pTObj && pTObj->GetType() == PDFOBJ_REFERENCE) {
+    if (ToReference(pTObj)) {
       CPDF_Object* pClone = pTObj->Clone(TRUE);
-      if (pClone) {
+      if (pClone)
         pDict->SetAt("T", pClone);
-      } else {
+      else
         pDict->SetAtName("T", "");
-      }
     }
     m_pFieldTree->SetField(csWName, pField);
   }
diff --git a/core/src/fpdfdoc/doc_tagged.cpp b/core/src/fpdfdoc/doc_tagged.cpp
index f74aa7f6f5..f1877c6573 100644
--- a/core/src/fpdfdoc/doc_tagged.cpp
+++ b/core/src/fpdfdoc/doc_tagged.cpp
@@ -173,10 +173,10 @@ FX_BOOL CPDF_StructTreeImpl::AddTopLevelNode(CPDF_Dictionary* pDict,
     FX_DWORD i;
     FX_BOOL bSave = FALSE;
     for (i = 0; i < pTopKids->GetCount(); i++) {
-      CPDF_Object* pKidRef = pTopKids->GetElement(i);
-      if (!pKidRef || pKidRef->GetType() != PDFOBJ_REFERENCE)
+      CPDF_Reference* pKidRef = ToReference(pTopKids->GetElement(i));
+      if (!pKidRef)
         continue;
-      if (((CPDF_Reference*)pKidRef)->GetRefObjNum() != pDict->GetObjNum())
+      if (pKidRef->GetRefObjNum() != pDict->GetObjNum())
         continue;
 
       if (m_Kids[i])
@@ -225,8 +225,8 @@ void CPDF_StructElementImpl::Release() {
 void CPDF_StructElementImpl::LoadKids(CPDF_Dictionary* pDict) {
   CPDF_Object* pObj = pDict->GetElement(FX_BSTRC("Pg"));
   FX_DWORD PageObjNum = 0;
-  if (pObj && pObj->GetType() == PDFOBJ_REFERENCE)
-    PageObjNum = ((CPDF_Reference*)pObj)->GetRefObjNum();
+  if (CPDF_Reference* pRef = ToReference(pObj))
+    PageObjNum = pRef->GetRefObjNum();
 
   CPDF_Object* pKids = pDict->GetElementValue(FX_BSTRC("K"));
   if (!pKids)
@@ -264,20 +264,18 @@ void CPDF_StructElementImpl::LoadKid(FX_DWORD PageObjNum,
   if (!pKidDict)
     return;
 
-  CPDF_Object* pPageObj = pKidDict->GetElement(FX_BSTRC("Pg"));
-  if (pPageObj && pPageObj->GetType() == PDFOBJ_REFERENCE) {
-    PageObjNum = ((CPDF_Reference*)pPageObj)->GetRefObjNum();
-  }
+  if (CPDF_Reference* pRef = ToReference(pKidDict->GetElement(FX_BSTRC("Pg"))))
+    PageObjNum = pRef->GetRefObjNum();
+
   CFX_ByteString type = pKidDict->GetString(FX_BSTRC("Type"));
   if (type == FX_BSTRC("MCR")) {
     if (m_pTree->m_pPage && m_pTree->m_pPage->GetObjNum() != PageObjNum) {
       return;
     }
     pKid->m_Type = CPDF_StructKid::StreamContent;
-    CPDF_Object* pStreamObj = pKidDict->GetElement(FX_BSTRC("Stm"));
-    if (pStreamObj && pStreamObj->GetType() == PDFOBJ_REFERENCE) {
-      pKid->m_StreamContent.m_RefObjNum =
-          ((CPDF_Reference*)pStreamObj)->GetRefObjNum();
+    if (CPDF_Reference* pRef =
+            ToReference(pKidDict->GetElement(FX_BSTRC("Stm")))) {
+      pKid->m_StreamContent.m_RefObjNum = pRef->GetRefObjNum();
     } else {
       pKid->m_StreamContent.m_RefObjNum = 0;
     }
@@ -288,9 +286,9 @@ void CPDF_StructElementImpl::LoadKid(FX_DWORD PageObjNum,
       return;
     }
     pKid->m_Type = CPDF_StructKid::Object;
-    CPDF_Object* pObj = pKidDict->GetElement(FX_BSTRC("Obj"));
-    if (pObj && pObj->GetType() == PDFOBJ_REFERENCE) {
-      pKid->m_Object.m_RefObjNum = ((CPDF_Reference*)pObj)->GetRefObjNum();
+    if (CPDF_Reference* pObj =
+            ToReference(pKidDict->GetElement(FX_BSTRC("Obj")))) {
+      pKid->m_Object.m_RefObjNum = pObj->GetRefObjNum();
     } else {
       pKid->m_Object.m_RefObjNum = 0;
     }