Extract external file systems handling from isolated context.

chrome/browser/intents/device_attached_intent_source.cc

 // 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/intents/device_attached_intent_source.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/file_path.h"
@@ skipping 110 matching lines @@
                      task.get()));
 }
 
 void DeviceAttachedIntentSource::DispatchIntentsForService(
     const base::SystemMonitor::RemovableStorageInfo& device_info) {
   // Store the media device info locally.
   device_id_map_.insert(std::make_pair(device_info.device_id, device_info));
 
   std::string device_name(UTF16ToUTF8(device_info.name));
   const FilePath device_path(device_info.location);
-
   // TODO(kinuko, kmadhusu): Use a different file system type for MTP.
   // TODO(kmadhusu): To manage the registered file systems efficiently, register
   // the attached device media file system using MediaFileSystemRegistry.
   const std::string fs_id = fileapi::IsolatedContext::GetInstance()->
       RegisterFileSystemForPath(fileapi::kFileSystemTypeNativeMedia,
                                 device_path, &device_name);
 
   DCHECK(!fs_id.empty());
   webkit_glue::WebIntentData intent(
       UTF8ToUTF16(kAction), UTF8ToUTF16(kIntentType), device_name, fs_id);
 
   delegate_->WebIntentDispatch(NULL  /* no WebContents */,
                                content::WebIntentsDispatcher::Create(intent));
 }
 
 void DeviceAttachedIntentSource::OnRemovableStorageDetached(
     const std::string& id) {
   DeviceIdToInfoMap::iterator it = device_id_map_.find(id);
   if (it == device_id_map_.end())
     return;
 
   FilePath path(it->second.location);
   fileapi::IsolatedContext::GetInstance()->RevokeFileSystemByPath(path);
   device_id_map_.erase(it);
 }