Re-enable warning 4701 for GN build and some cleanup

core/fpdfapi/fpdf_edit/fpdf_edit_doc.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 <limits.h>
 
 #include "core/fpdfapi/fpdf_font/include/cpdf_font.h"
 #include "core/fpdfapi/fpdf_font/include/cpdf_fontencoding.h"
@@ skipping 336 matching lines @@
     CPDF_Array* pWidths = new CPDF_Array;
     for (int i = 0; i < 224; i++) {
       pWidths->AddInteger(char_widths[i]);
     }
     pBaseDict->SetAt("Widths", pWidths);
   } else {
     flags |= PDFFONT_NONSYMBOLIC;
     pFontDict = new CPDF_Dictionary;
     CFX_ByteString cmap;
     CFX_ByteString ordering;
-    int supplement;
+    int supplement = 0;
     CPDF_Array* pWidthArray = new CPDF_Array;
     switch (pLogFont->lfCharSet) {
       case CHINESEBIG5_CHARSET:
         cmap = bVert ? "ETenms-B5-V" : "ETenms-B5-H";
         ordering = "CNS1";
         supplement = 4;
         pWidthArray->AddInteger(1);
         _InsertWidthArray(hDC, 0x20, 0x7e, pWidthArray);
         break;
       case GB2312_CHARSET:
@@ skipping 782 matching lines @@
 void FPDFAPI_FlatPageAttr(CPDF_Dictionary* pPageDict,
                           const CFX_ByteStringC& name) {
   if (pPageDict->KeyExist(name)) {
     return;
   }
   CPDF_Object* pObj = FPDFAPI_GetPageAttr(pPageDict, name);
   if (pObj) {
     pPageDict->SetAt(name, pObj->Clone());
   }
 }