Remove implicit conversions and some cleanup

core/src/fpdfdoc/doc_formfield.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/fpdfdoc/fpdf_doc.h"
 #include "core/src/fpdfdoc/doc_utils.h"
 
 FX_BOOL PDF_FormField_IsUnison(CPDF_FormField* pField) {
@@ skipping 217 matching lines @@
     case RichText:
     case File:
       return FIELDTYPE_TEXTFIELD;
     case Sign:
       return FIELDTYPE_SIGNATURE;
     default:
       break;
   }
   return FIELDTYPE_UNKNOWN;
 }
+
 CPDF_AAction CPDF_FormField::GetAdditionalAction() {
   CPDF_Object* pObj = FPDF_GetFieldAttr(m_pDict, "AA");
-  if (!pObj) {
-    return NULL;
-  }
-  return pObj->GetDict();
+  return CPDF_AAction(pObj ? pObj->GetDict() : nullptr);
 }
+
 CFX_WideString CPDF_FormField::GetAlternateName() {
   CPDF_Object* pObj = FPDF_GetFieldAttr(m_pDict, "TU");
   if (!pObj) {
     return L"";
   }
   return pObj->GetUnicodeText();
 }
 CFX_WideString CPDF_FormField::GetMappingName() {
   CPDF_Object* pObj = FPDF_GetFieldAttr(m_pDict, "TM");
   if (!pObj) {
@@ skipping 828 matching lines @@
     pFontDict = m_pForm->m_pFormDict->GetDictBy("DR")
                     ->GetDictBy("Font")
                     ->GetDictBy(font_name);
 
   if (!pFontDict) {
     return;
   }
   m_pFont = m_pForm->m_pDocument->LoadFont(pFontDict);
   m_FontSize = FX_atof(syntax.GetWord());
 }