Use enum class for subtypes of CPDF_Annot.

fpdfsdk/javascript/Annot.cpp

 // Copyright 2016 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 "fpdfsdk/javascript/Annot.h"
 
 #include "fpdfsdk/javascript/JS_Define.h"
 #include "fpdfsdk/javascript/JS_Object.h"
@@ skipping 62 matching lines @@
 
 FX_BOOL Annot::type(IJS_Context* cc,
                     CJS_PropValue& vp,
                     CFX_WideString& sError) {
   if (vp.IsSetting()) {
     CJS_Context* pContext = static_cast<CJS_Context*>(cc);
     sError = JSGetStringFromID(pContext, IDS_STRING_JSREADONLY);
     return FALSE;
   }
 
-  vp << m_BAAnnot->GetAnnotSubtype();
+  vp << CPDF_Annot::AnnotSubtypeToString(m_BAAnnot->GetAnnotSubtype());
   return TRUE;
 }
 
 void Annot::SetSDKAnnot(CPDFSDK_BAAnnot* annot) {
   m_BAAnnot = annot;
 }