Make CPDF_Object::GetString() a virtual method.

core/src/fpdfdoc/doc_link.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../../include/fpdfdoc/fpdf_doc.h"
 
 CPDF_LinkList::~CPDF_LinkList()
 {
@@ skipping 55 matching lines @@
 {
     CPDF_Array* pAnnotList = pPage->m_pFormDict->GetArray("Annots");
     if (pAnnotList == NULL) {
         return;
     }
     for (FX_DWORD i = 0; i < pAnnotList->GetCount(); i ++) {
         CPDF_Dictionary* pAnnot = pAnnotList->GetDict(i);
         if (pAnnot == NULL) {
             continue;
         }
-        if (pAnnot->GetString("Subtype") != "Link") {
+        if (pAnnot->GetStringAt("Subtype") != "Link") {
             continue;
         }
         pList->Add(pAnnot);
     }
 }
 CPDF_Rect CPDF_Link::GetRect()
 {
     return m_pDict->GetRect("Rect");
 }
 CPDF_Dest CPDF_Link::GetDest(CPDF_Document* pDoc)
 {
     CPDF_Object* pDest = m_pDict->GetElementValue("Dest");
     if (pDest == NULL) {
         return CPDF_Dest();
     }
     if (pDest->GetType() == PDFOBJ_STRING || pDest->GetType() == PDFOBJ_NAME) {
         CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
         CFX_ByteStringC name = pDest->GetString();
         return CPDF_Dest(name_tree.LookupNamedDest(pDoc, name));
     }
     if (pDest->GetType() == PDFOBJ_ARRAY) {
         return CPDF_Dest((CPDF_Array*)pDest);
     }
     return CPDF_Dest();
 }
 CPDF_Action CPDF_Link::GetAction()
 {
     return CPDF_Action(m_pDict->GetDict("A"));
 }