Make CPDF_Object::GetString() a virtual method.

core/src/fpdfdoc/doc_annot.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 "../../../third_party/base/nonstd_unique_ptr.h"
 #include "../../include/fpdfdoc/fpdf_doc.h"
 #include "../../include/fpdfapi/fpdf_pageobj.h"
 
@@ skipping 184 matching lines @@
         ap_entry = "N";
     }
     CPDF_Object* psub = pAP->GetElementValue(ap_entry);
     if (psub == NULL) {
         return NULL;
     }
     CPDF_Stream* pStream = NULL;
     if (psub->GetType() == PDFOBJ_STREAM) {
         pStream = (CPDF_Stream*)psub;
     } else if (psub->GetType() == PDFOBJ_DICTIONARY) {
-        CFX_ByteString as = pAnnotDict->GetString("AS");
+        CFX_ByteString as = pAnnotDict->GetStringAt("AS");
         if (as.IsEmpty()) {
-            CFX_ByteString value = pAnnotDict->GetString(FX_BSTRC("V"));
+            CFX_ByteString value = pAnnotDict->GetStringAt("V");
             if (value.IsEmpty()) {
                 CPDF_Dictionary* pDict = pAnnotDict->GetDict(FX_BSTRC("Parent"));
-                value = pDict ? pDict->GetString(FX_BSTRC("V")) : CFX_ByteString();
+                value = pDict ? pDict->GetStringAt("V") : CFX_ByteString();
             }
             if (value.IsEmpty() || !((CPDF_Dictionary*)psub)->KeyExist(value)) {
                 as = FX_BSTRC("Off");
             } else {
                 as = value;
             }
         }
         pStream = ((CPDF_Dictionary*)psub)->GetStream(as);
     }
     return pStream;
@@ skipping 91 matching lines @@
                 }
                 if (i == nLen) {
                     return;
                 }
                 style_char = 'D';
             }
         } else {
             width = 1;
         }
     } else {
-        CFX_ByteString style = pBS->GetString("S");
+        CFX_ByteString style = pBS->GetStringAt("S");
         pDashArray = pBS->GetArray("D");
         style_char = style[1];
         width = pBS->GetNumber("W");
     }
     if (width <= 0) {
         return;
     }
     CPDF_Array* pColor = m_pAnnotDict->GetArray("C");
     FX_DWORD argb = 0xff000000;
     if (pColor != NULL) {
@@ skipping 29 matching lines @@
     GetRect(rect);
     CPDF_PathData path;
     width /= 2;
     path.AppendRect(rect.left + width, rect.bottom + width, rect.right - width, rect.top - width);
     int fill_type = 0;
     if (pOptions && (pOptions->m_Flags & RENDER_NOPATHSMOOTH)) {
         fill_type |= FXFILL_NOPATHSMOOTH;
     }
     pDevice->DrawPath(&path, pUser2Device, &graph_state, argb, argb, fill_type);
 }