text: // Copyright (c) 2012 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 "chrome/browser/renderer_host/pepper/chrome_browser_pepper_host_factory.h"
  
  #include "build/build_config.h"
  #include "chrome/browser/renderer_host/pepper/pepper_isolated_file_system_message_filter.h"
  #include "content/public/browser/browser_ppapi_host.h"
  #include "ppapi/host/message_filter_host.h"
  #include "ppapi/host/ppapi_host.h"
  #include "ppapi/host/resource_host.h"
  #include "ppapi/proxy/ppapi_messages.h"
  #include "ppapi/shared_impl/ppapi_permissions.h"
  
  using ppapi::host::MessageFilterHost;
  using ppapi::host::ResourceHost;
  using ppapi::host::ResourceMessageFilter;
  
  ChromeBrowserPepperHostFactory::ChromeBrowserPepperHostFactory(
      content::BrowserPpapiHost* host)
      : host_(host) {}
  
  ChromeBrowserPepperHostFactory::~ChromeBrowserPepperHostFactory() {}
  
  std::unique_ptr<ResourceHost>
  ChromeBrowserPepperHostFactory::CreateResourceHost(
      ppapi::host::PpapiHost* host,
      PP_Resource resource,
      PP_Instance instance,
      const IPC::Message& message) {
    DCHECK(host == host_->GetPpapiHost());
  
    // Make sure the plugin is giving us a valid instance for this resource.
    if (!host_->IsValidInstance(instance))
      return nullptr;
  
    // Permissions for the following interfaces will be checked at the
    // time of the corresponding instance's methods calls (because
    // permission check can be performed only on the UI
    // thread). Currently these interfaces are available only for
    // whitelisted apps which may not have access to the other private
    // interfaces.
    if (message.type() != PpapiHostMsg_IsolatedFileSystem_Create::ID)
      return nullptr;
  
    PepperIsolatedFileSystemMessageFilter* isolated_fs_filter =
        PepperIsolatedFileSystemMessageFilter::Create(instance, host_);
    if (!isolated_fs_filter)
      return nullptr;
    return std::make_unique<MessageFilterHost>(host, instance, resource,
                                               isolated_fs_filter);
  }
  