Add type cast definitions for CPDF_Stream.

core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp

Index: core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
diff --git a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
index 8972201b660df94b5f605b5b4d7e651c9f3639b5..02f0933f360089f2677ae74ed1e2664466a0b51a 100644
--- a/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
+++ b/core/src/fpdfapi/fpdf_font/fpdf_font_cid.cpp
@@ -1215,9 +1215,8 @@ FX_BOOL CPDF_CIDFont::_Load() {
             ->GetPageModule()
             ->GetFontGlobals()
             ->m_CMapManager.GetPredefinedCMap(cmap, m_pFontFile && m_bType1);
-  } else if (pEncoding->GetType() == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = pEncoding->AsStream()) {
     m_pAllocatedCMap = m_pCMap = new CPDF_CMap;
-    CPDF_Stream* pStream = (CPDF_Stream*)pEncoding;
     CPDF_StreamAcc acc;
     acc.LoadAllData(pStream, FALSE);
     m_pCMap->LoadEmbedded(acc.GetData(), acc.GetSize());
@@ -1265,9 +1264,9 @@ FX_BOOL CPDF_CIDFont::_Load() {
       CPDF_Object* pmap =
           pCIDFontDict->GetElementValue(FX_BSTRC("CIDToGIDMap"));
       if (pmap) {
-        if (pmap->GetType() == PDFOBJ_STREAM) {
+        if (CPDF_Stream* pStream = pmap->AsStream()) {
           m_pCIDToGIDMap = new CPDF_StreamAcc;
-          m_pCIDToGIDMap->LoadAllData((CPDF_Stream*)pmap, FALSE);
+          m_pCIDToGIDMap->LoadAllData(pStream, FALSE);
         } else if (pmap->GetString() == FX_BSTRC("Identity")) {
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_APPLE_
           if (m_pFontFile) {