Move exports from Document to Module

sky/engine/core/app/AbstractModule.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/app/AbstractModule.h"
 
 namespace blink {
 
 AbstractModule::AbstractModule(ExecutionContext* context,
                                Document* document,
                                const String& url)
   : ContextLifecycleObserver(context),
     document_(document),
     url_(url) {
+  document_->setModule(this);
 }
 
 AbstractModule::~AbstractModule() {
+  document_->setModule(nullptr);
 }
 
 ExecutionContext* AbstractModule::executionContext() const {
   return ContextLifecycleObserver::executionContext();
 }
 
 } // namespace blink