Make MediaFileUtil run on thread pool.

webkit/fileapi/file_system_context.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 "webkit/fileapi/file_system_context.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/stl_util.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 28 matching lines @@
 void DidOpenFileSystem(FileSystemContext::OpenFileSystemCallback callback,
                        const GURL& filesystem_root,
                        const std::string& filesystem_name,
                        base::PlatformFileError error) {
   callback.Run(error, filesystem_name, filesystem_root);
 }
 
 }  // anonymous namespace
 
 FileSystemContext::FileSystemContext(
+    base::SequencedTaskRunner* media_task_runner,
     base::SequencedTaskRunner* file_task_runner,
     base::SingleThreadTaskRunner* io_task_runner,
     quota::SpecialStoragePolicy* special_storage_policy,
     quota::QuotaManagerProxy* quota_manager_proxy,
     const FilePath& profile_path,
     const FileSystemOptions& options)
     : file_task_runner_(file_task_runner),
       io_task_runner_(io_task_runner),
       quota_manager_proxy_(quota_manager_proxy),
       sandbox_provider_(
           new SandboxMountPointProvider(
               file_task_runner,
               profile_path,
               options)),
-      isolated_provider_(new IsolatedMountPointProvider) {
+      isolated_provider_(new IsolatedMountPointProvider(media_task_runner)) {
   if (quota_manager_proxy) {
     quota_manager_proxy->RegisterClient(CreateQuotaClient(
             this, options.is_incognito()));
   }
 #if defined(OS_CHROMEOS)
   external_provider_.reset(
       new chromeos::CrosMountPointProvider(special_storage_policy));
 #endif
 }
 
@@ skipping 132 matching lines @@
   if (!io_task_runner_->RunsTasksOnCurrentThread() &&
       io_task_runner_->DeleteSoon(FROM_HERE, this)) {
     return;
   }
   STLDeleteContainerPairSecondPointers(provider_map_.begin(),
                                        provider_map_.end());
   delete this;
 }
 
 }  // namespace fileapi