Add type cast definitions for CPDF_Stream.

This Cl adds ToStream, CPDF_Object::AsStream and CPDF_Object::IsStream and
updates the src to use them as needed.

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

Review URL: https://codereview.chromium.org/1402413004 .

4 files changed, 13 insertions, 13 deletions

diff --git a/fpdfsdk/src/fpdf_flatten.cpp b/fpdfsdk/src/fpdf_flatten.cpp
index f4d49ce182..39441c4aef 100644
--- a/fpdfsdk/src/fpdf_flatten.cpp
+++ b/fpdfsdk/src/fpdf_flatten.cpp
@@ -211,7 +211,7 @@ void SetPageContents(CFX_ByteString key,
   switch (iType) {
     case PDFOBJ_STREAM: {
       pContentsArray = new CPDF_Array;
-      CPDF_Stream* pContents = (CPDF_Stream*)pContentsObj;
+      CPDF_Stream* pContents = pContentsObj->AsStream();
       FX_DWORD dwObjNum = pDocument->AddIndirectObject(pContents);
       CPDF_StreamAcc acc;
       acc.LoadAllData(pContents);
@@ -447,15 +447,14 @@ DLLEXPORT int STDCALL FPDFPage_Flatten(FPDF_PAGE page, int nFlag) {
             if (pFirstObj->GetType() == PDFOBJ_REFERENCE)
               pFirstObj = pFirstObj->GetDirect();
 
-            if (pFirstObj->GetType() != PDFOBJ_STREAM)
+            if (!pFirstObj->IsStream())
               continue;
 
-            pAPStream = (CPDF_Stream*)pFirstObj;
+            pAPStream = pFirstObj->AsStream();
           }
         }
       }
     }
-
     if (!pAPStream)
       continue;
 
diff --git a/fpdfsdk/src/fpdf_transformpage.cpp b/fpdfsdk/src/fpdf_transformpage.cpp
index d2ad26bf64..20713fe07d 100644
--- a/fpdfsdk/src/fpdf_transformpage.cpp
+++ b/fpdfsdk/src/fpdf_transformpage.cpp
@@ -144,7 +144,7 @@ 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 (pDirectObj->GetType() == PDFOBJ_STREAM) {
+      } else if (pDirectObj->IsStream()) {
         pContentArray = new CPDF_Array();
         pContentArray->AddReference(pDoc, pStream->GetObjNum());
         pContentArray->AddReference(pDoc, pDirectObj->GetObjNum());
@@ -162,16 +162,17 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFPage_TransFormWithClip(FPDF_PAGE page,
     if (pPattenDict) {
       FX_POSITION pos = pPattenDict->GetStartPos();
       while (pos) {
-        CPDF_Dictionary* pDict = NULL;
+        CPDF_Dictionary* pDict = nullptr;
         CFX_ByteString key;
         CPDF_Object* pObj = pPattenDict->GetNextElement(pos, key);
         if (pObj->GetType() == PDFOBJ_REFERENCE)
           pObj = pObj->GetDirect();
-        if (pObj->IsDictionary()) {
+
+        if (pObj->IsDictionary())
           pDict = pObj->AsDictionary();
-        } else if (pObj->GetType() == PDFOBJ_STREAM) {
-          pDict = ((CPDF_Stream*)pObj)->GetDict();
-        } else
+        else if (CPDF_Stream* pStream = pObj->AsStream())
+          pDict = pStream->GetDict();
+        else
           continue;
 
         CFX_AffineMatrix m = pDict->GetMatrix(FX_BSTRC("Matrix"));
@@ -313,7 +314,7 @@ 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 (pDirectObj->GetType() == PDFOBJ_STREAM) {
+      } else if (pDirectObj->IsStream()) {
         pContentArray = new CPDF_Array();
         pContentArray->AddReference(pDoc, pStream->GetObjNum());
         pContentArray->AddReference(pDoc, pDirectObj->GetObjNum());
diff --git a/fpdfsdk/src/fpdfppo.cpp b/fpdfsdk/src/fpdfppo.cpp
index 7b589b585f..c9df813789 100644
--- a/fpdfsdk/src/fpdfppo.cpp
+++ b/fpdfsdk/src/fpdfppo.cpp
@@ -247,7 +247,7 @@ FX_BOOL CPDF_PageOrganizer::UpdateReference(CPDF_Object* pObj,
       break;
     }
     case PDFOBJ_STREAM: {
-      CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+      CPDF_Stream* pStream = pObj->AsStream();
       CPDF_Dictionary* pDict = pStream->GetDict();
       if (pDict) {
         if (!UpdateReference(pDict, pDoc, pObjNumberMap))
diff --git a/fpdfsdk/src/fsdk_baseform.cpp b/fpdfsdk/src/fsdk_baseform.cpp
index 3b845b017e..e083220fe2 100644
--- a/fpdfsdk/src/fsdk_baseform.cpp
+++ b/fpdfsdk/src/fsdk_baseform.cpp
@@ -62,7 +62,7 @@ FX_BOOL CPDFSDK_Widget::IsWidgetAppearanceValid(
     case FIELDTYPE_LISTBOX:
     case FIELDTYPE_TEXTFIELD:
     case FIELDTYPE_SIGNATURE:
-      return psub->GetType() == PDFOBJ_STREAM;
+      return psub->IsStream();
     case FIELDTYPE_CHECKBOX:
     case FIELDTYPE_RADIOBUTTON:
       if (CPDF_Dictionary* pSubDict = psub->AsDictionary()) {