Add some consts and remove more casts in core/

core/fpdfdoc/doc_form.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 <vector>
 
 #include "core/fpdfapi/fpdf_font/include/cpdf_fontencoding.h"
 #include "core/fpdfapi/fpdf_page/include/cpdf_page.h"
@@ skipping 602 matching lines @@
   csNewFieldName = csSub;
   return TRUE;
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(CFX_WideString& csNewFieldName,
                                           int iType) {
   return ValidateFieldName(csNewFieldName, iType, nullptr, nullptr);
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(const CPDF_FormField* pField,
                                           CFX_WideString& csNewFieldName) {
   return pField && !csNewFieldName.IsEmpty() &&
-         ValidateFieldName(csNewFieldName,
-                           ((CPDF_FormField*)pField)->GetFieldType(), pField,
+         ValidateFieldName(csNewFieldName, pField->GetFieldType(), pField,
                            nullptr);
 }
 FX_BOOL CPDF_InterForm::ValidateFieldName(const CPDF_FormControl* pControl,
                                           CFX_WideString& csNewFieldName) {
   if (!pControl || csNewFieldName.IsEmpty()) {
     return FALSE;
   }
-  CPDF_FormField* pField = ((CPDF_FormControl*)pControl)->GetField();
+  CPDF_FormField* pField = pControl->GetField();
   return ValidateFieldName(csNewFieldName, pField->GetFieldType(), pField,
                            pControl);
 }
 int CPDF_InterForm::CompareFieldName(const CFX_ByteString& name1,
                                      const CFX_ByteString& name2) {
   if (name1.GetLength() == name2.GetLength()) {
     return name1 == name2 ? 1 : 0;
   }
   const FX_CHAR* ptr1 = name1.c_str();
   const FX_CHAR* ptr2 = name2.c_str();
@@ skipping 547 matching lines @@
     FDF_ImportField(pField, L"", bNotify);
   }
   if (bNotify && m_pFormNotify)
     m_pFormNotify->AfterFormImportData(this);
   return TRUE;
 }
 
 void CPDF_InterForm::SetFormNotify(IPDF_FormNotify* pNotify) {
   m_pFormNotify = pNotify;
 }