Don't keep the lazy background page alive after a view with a Pepper plugin is closed

ppapi/tests/extensions/popup/module.cc

 // Copyright 2015 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 "ppapi/cpp/instance.h"
 #include "ppapi/cpp/module.h"
 
 namespace {
 
 class Module : public pp::Module {
  public:
   virtual pp::Instance* CreateInstance(PP_Instance instance) {
     return new pp::Instance(instance);
   }
 };
 
 }  // namespace
 
 namespace pp {
 
 Module* CreateModule() {
   return new ::Module();
 }
 
 }  // namespace pp