Make CPDF_Object::GetString() a virtual method.

core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp

Index: core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
index 685ee047aa4fb3d426ef9c8e9547fec42c0c8b8e..251697ea865512bc22c088a4367c4b28426307db 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_parser.cpp
@@ -281,7 +281,7 @@ FX_DWORD CPDF_Parser::SetEncryptHandler()
         }
         m_Syntax.SetEncrypt(pCryptoHandler);
     } else if (m_pEncryptDict) {
-        CFX_ByteString filter = m_pEncryptDict->GetString(FX_BSTRC("Filter"));
+        CFX_ByteString filter = m_pEncryptDict->GetStringAt("Filter");
         CPDF_SecurityHandler* pSecurityHandler = NULL;
         FX_DWORD err = PDFPARSE_ERROR_HANDLER;
         if (filter == FX_BSTRC("Standard")) {
@@ -787,7 +787,7 @@ FX_BOOL CPDF_Parser::RebuildCrossRef()
                                         CPDF_Dictionary* pDict = pStream->GetDict();
                                         if (pDict) {
                                             if (pDict->KeyExist(FX_BSTRC("Type"))) {
-                                                CFX_ByteString bsValue = pDict->GetString(FX_BSTRC("Type"));
+                                                CFX_ByteString bsValue = pDict->GetStringAt("Type");
                                                 if (bsValue == FX_BSTRC("XRef") && pDict->KeyExist(FX_BSTRC("Size"))) {
                                                     CPDF_Object* pRoot = pDict->GetElement(FX_BSTRC("Root"));
                                                     if (pRoot && pRoot->GetDict() && pRoot->GetDict()->GetElement(FX_BSTRC("Pages"))) {
@@ -1464,7 +1464,7 @@ FX_DWORD CPDF_Parser::GetPermissions(FX_BOOL bCheckRevision)
         return (FX_DWORD) - 1;
     }
     FX_DWORD dwPermission = m_pSecurityHandler->GetPermissions();
-    if (m_pEncryptDict && m_pEncryptDict->GetString(FX_BSTRC("Filter")) == FX_BSTRC("Standard")) {
+    if (m_pEncryptDict && m_pEncryptDict->GetStringAt("Filter") == "Standard") {
         dwPermission &= 0xFFFFFFFC;
         dwPermission |= 0xFFFFF0C0;
         if(bCheckRevision && m_pEncryptDict->GetInteger(FX_BSTRC("R")) == 2) {
@@ -3048,7 +3048,9 @@ FX_BOOL CPDF_DataAvail::IsObjectsAvail(CFX_PtrArray& obj_array, FX_BOOL bParsePa
                 pObj = pObj->GetDict();
             case PDFOBJ_DICTIONARY: {
                     CPDF_Dictionary *pDict = pObj->GetDict();
-                    if (pDict && pDict->GetString("Type") == "Page" && !bParsePage) {
+                    if (!bParsePage &&
+                        pDict &&
+                        pDict->GetStringAt("Type") == "Page") {
                         continue;
                     }
                     FX_POSITION pos = pDict->GetStartPos();
@@ -3479,7 +3481,7 @@ FX_BOOL CPDF_DataAvail::CheckPage(IFX_DownloadHints* pHints)
             pObj->Release();
             continue;
         }
-        CFX_ByteString type = pObj->GetDict()->GetString(FX_BSTRC("Type"));
+        CFX_ByteString type = pObj->GetDict()->GetStringAt("Type");
         if (type == FX_BSTRC("Pages")) {
             m_PagesArray.Add(pObj);
             continue;
@@ -4163,7 +4165,7 @@ FX_BOOL CPDF_DataAvail::CheckUnkownPageNode(FX_DWORD dwPageNo, CPDF_PageNode *pP
     }
     pPageNode->m_dwPageNo = dwPageNo;
     CPDF_Dictionary* pDict = pPage->GetDict();
-    CFX_ByteString type = pDict ? pDict->GetString(FX_BSTRC("Type")) : CFX_ByteString();
+    CFX_ByteString type = pDict ? pDict->GetStringAt("Type") : CFX_ByteString();
     if (type == FX_BSTRC("Pages")) {
         pPageNode->m_type = PDF_PAGENODE_PAGES;
         CPDF_Object *pKids = pDict->GetElement(FX_BSTRC("Kids"));