Fix leaked array buffer allocators of isolates

fxjs/cfxjse_isolatetracker.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 "fxjs/cfxjse_isolatetracker.h"
 
 #include <algorithm>
 
 CFXJSE_IsolateTracker::CFXJSE_IsolateTracker() {}
 
 CFXJSE_IsolateTracker::~CFXJSE_IsolateTracker() {}
 
-void CFXJSE_IsolateTracker::Append(v8::Isolate* pIsolate) {
+void CFXJSE_IsolateTracker::Append(
+    v8::Isolate* pIsolate,
+    std::unique_ptr<v8::ArrayBuffer::Allocator> alloc) {
   m_OwnedIsolates.push_back(pIsolate);
+  m_AllocatorMap[pIsolate] = std::move(alloc);
 }
 
 void CFXJSE_IsolateTracker::Remove(
     v8::Isolate* pIsolate,
     CFXJSE_IsolateTracker::DisposeCallback lpfnDisposeCallback) {
   auto it = std::find(m_OwnedIsolates.begin(), m_OwnedIsolates.end(), pIsolate);
   bool bFound = it != m_OwnedIsolates.end();
   if (bFound)
     m_OwnedIsolates.erase(it);
   lpfnDisposeCallback(pIsolate, bFound);
+
+  m_AllocatorMap.erase(pIsolate);
 }
 
 void CFXJSE_IsolateTracker::RemoveAll(
     CFXJSE_IsolateTracker::DisposeCallback lpfnDisposeCallback) {
   for (v8::Isolate* pIsolate : m_OwnedIsolates)
     lpfnDisposeCallback(pIsolate, true);
 
   m_OwnedIsolates.clear();
+  m_AllocatorMap.clear();
 }