Make CPDF_Object::GetString() a virtual method.

core/src/fpdfapi/fpdf_page/fpdf_page.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/fpdfapi/fpdf_page.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 #include "pageint.h"
 CPDF_PageObject* CPDF_PageObject::Create(int type)
@@ skipping 813 matching lines @@
 }
 void CPDF_PageObjects::LoadTransInfo()
 {
     if (m_pFormDict == NULL) {
         return;
     }
     CPDF_Dictionary* pGroup = m_pFormDict->GetDict(FX_BSTRC("Group"));
     if (pGroup == NULL) {
         return;
     }
-    if (pGroup->GetString(FX_BSTRC("S")) != FX_BSTRC("Transparency")) {
+    if (pGroup->GetStringAt("S") != "Transparency") {
         return;
     }
     m_Transparency |= PDFTRANS_GROUP;
     if (pGroup->GetInteger(FX_BSTRC("I"))) {
         m_Transparency |= PDFTRANS_ISOLATED;
     }
     if (pGroup->GetInteger(FX_BSTRC("K"))) {
         m_Transparency |= PDFTRANS_KNOCKOUT;
     }
 }
@@ skipping 224 matching lines @@
     matrix = m_PageMatrix;
     matrix.Concat(display_matrix);
 }
 CPDF_ParseOptions::CPDF_ParseOptions()
 {
     m_bTextOnly = FALSE;
     m_bMarkedContent = TRUE;
     m_bSeparateForm = TRUE;
     m_bDecodeInlineImage = FALSE;
 }