Don't put timers with ID == 0 into the global timer map.

fpdfsdk/javascript/app.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 "fpdfsdk/javascript/app.h"
 
 #include <map>
 #include <memory>
@@ skipping 57 matching lines @@
     : m_nTimerID(0),
       m_pEmbedObj(pObj),
       m_bProcessing(false),
       m_nType(nType),
       m_dwTimeOut(dwTimeOut),
       m_swJScript(script),
       m_pRuntime(pRuntime),
       m_pFormFillEnv(pFormFillEnv) {
   CFX_SystemHandler* pHandler = m_pFormFillEnv->GetSysHandler();
   m_nTimerID = pHandler->SetTimer(dwElapse, Trigger);
-  (*GetGlobalTimerMap())[m_nTimerID] = this;
+  if (m_nTimerID)
+    (*GetGlobalTimerMap())[m_nTimerID] = this;
 }
 
 GlobalTimer::~GlobalTimer() {
   if (!m_nTimerID)
     return;
 
   if (GetRuntime())
     m_pFormFillEnv->GetSysHandler()->KillTimer(m_nTimerID);
 
   GetGlobalTimerMap()->erase(m_nTimerID);
@@ skipping 703 matching lines @@
 bool app::media(IJS_Context* cc, CJS_PropValue& vp, CFX_WideString& sError) {
   return false;
 }
 
 bool app::execDialog(IJS_Context* cc,
                      const std::vector<CJS_Value>& params,
                      CJS_Value& vRet,
                      CFX_WideString& sError) {
   return true;
 }