Only call DefineJSObjects() once for the global V8 isolate.

fpdfsdk/src/javascript/JS_Runtime.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 "../../include/javascript/JavaScript.h"
 #include "../../include/javascript/IJavaScript.h"
 #include "../../include/javascript/JS_EventHandler.h"
 #include "../../include/javascript/JS_Runtime.h"
@@ skipping 27 matching lines @@
   if (pPlatform->version <= 2) {
     unsigned int embedderDataSlot = 0;
     v8::Isolate* pExternalIsolate = nullptr;
     if (pPlatform->version == 2) {
       pExternalIsolate = reinterpret_cast<v8::Isolate*>(pPlatform->m_isolate);
       embedderDataSlot = pPlatform->m_v8EmbedderSlot;
     }
     FXJS_Initialize(embedderDataSlot, pExternalIsolate);
   }
   m_isolateManaged = FXJS_GetIsolate(&m_isolate);
-  DefineJSObjects();
+  if (m_isolateManaged || FXJS_GlobalIsolateRefCount() == 0)
+    DefineJSObjects();
 
   CJS_Context* pContext = (CJS_Context*)NewContext();
   FXJS_InitializeRuntime(GetIsolate(), this, pContext, m_context);
   ReleaseContext(pContext);
 }
 
 CJS_Runtime::~CJS_Runtime() {
   for (auto* obs : m_observers)
     obs->OnDestroyed();
 
@@ skipping 127 matching lines @@
 void CJS_Runtime::RemoveObserver(Observer* observer) {
   ASSERT(m_observers.find(observer) != m_observers.end());
   m_observers.erase(observer);
 }
 
 CFX_WideString ChangeObjName(const CFX_WideString& str) {
   CFX_WideString sRet = str;
   sRet.Replace(L"_", L".");
   return sRet;
 }