Remove dead code from CPDF_Metadata. Add missing nullptr check.

fpdfsdk/src/fpdf_ext.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 "../../core/include/fxcrt/fx_xml.h"
 #include "../../public/fpdf_ext.h"
 #include "../include/fsdk_define.h"
 
@@ skipping 70 matching lines @@
     CFX_ByteString cbString;
     if (pAnnotDict->KeyExist("FT")) {
       cbString = pAnnotDict->GetString("FT");
     }
     if (cbString.Compare("Sig") == 0) {
       FPDF_UnSupportError(FPDF_UNSP_ANNOT_SIG);
     }
   }
 }
 
-FX_BOOL CheckSharedForm(CXML_Element* pElement, CFX_ByteString cbName) {
+FX_BOOL CheckSharedForm(const CXML_Element* pElement, CFX_ByteString cbName) {
   int count = pElement->CountAttrs();
   int i = 0;
   for (i = 0; i < count; i++) {
     CFX_ByteString space, name;
     CFX_WideString value;
     pElement->GetAttrByIndex(i, space, name, value);
     if (space == FX_BSTRC("xmlns") && name == FX_BSTRC("adhocwf") &&
         value == L"http://ns.adobe.com/AcrobatAdhocWorkflow/1.0/") {
       CXML_Element* pVersion = pElement->GetElement("adhocwf", cbName);
       if (!pVersion)
@@ skipping 60 matching lines @@
               FPDF_UnSupportError(FPDF_UNSP_DOC_SHAREDREVIEW);
               return;
             }
           }
         }
       }
     }
   }
 
   // SharedForm
-  CPDF_Metadata metaData;
-  metaData.LoadDoc(pDoc);
-  CXML_Element* pElement = metaData.GetRoot();
+  CPDF_Metadata metaData(pDoc);
+  const CXML_Element* pElement = metaData.GetRoot();
   if (pElement)
     CheckSharedForm(pElement, "workflowType");
 
   // XFA Forms
   CPDF_InterForm* pInterForm = new CPDF_InterForm(pDoc, FALSE);
   if (pInterForm->HasXFAForm()) {
     FPDF_UnSupportError(FPDF_UNSP_DOC_XFAFORM);
   }
   delete pInterForm;
 }
@@ skipping 19 matching lines @@
     return PAGEMODE_USETHUMBS;
   if (strPageMode.EqualNoCase("FullScreen"))
     return PAGEMODE_FULLSCREEN;
   if (strPageMode.EqualNoCase("UseOC"))
     return PAGEMODE_USEOC;
   if (strPageMode.EqualNoCase("UseAttachments"))
     return PAGEMODE_USEATTACHMENTS;
 
   return PAGEMODE_UNKNOWN;
 }