Revert of file_manager: Migrate FILE thread to TaskScheduler

chrome/browser/chromeos/extensions/file_manager/file_manager_private_apitest.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 <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "chrome/browser/chromeos/extensions/file_manager/event_router.h"
 #include "chrome/browser/chromeos/file_manager/file_watcher.h"
 #include "chrome/browser/chromeos/file_manager/mount_test_util.h"
 #include "chrome/browser/chromeos/file_system_provider/provided_file_system_info.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "chrome/common/extensions/api/file_system_provider_capabilities/file_system_provider_capabilities_handler.h"
 #include "chrome/test/base/testing_profile.h"
+#include "chrome/test/base/ui_test_utils.h"
 #include "chromeos/dbus/cros_disks_client.h"
 #include "chromeos/disks/mock_disk_mount_manager.h"
 #include "components/drive/file_change.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/install_warning.h"
 #include "google_apis/drive/test_util.h"
 #include "storage/browser/fileapi/external_mount_points.h"
 
 using ::testing::_;
 using ::testing::ReturnRef;
@@ skipping 343 matching lines @@
   event_router_->AddFileWatch(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/a/d/e")),
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs-hash/root/a/d/e")),
       "extension_2", base::Bind(&AddFileWatchCallback));
 
   event_router_->AddFileWatch(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/aaa")),
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs-hash/root/aaa")),
       "extension_3", base::Bind(&AddFileWatchCallback));
 
-  // event_router->addFileWatch create some tasks which are performed on
-  // TaskScheduler. Wait until they are done.
-  base::TaskScheduler::GetInstance()->FlushForTesting();
-  // We also wait the UI thread here, since some tasks which are performed
-  // above message loop back results to the UI thread.
+  // event_router->addFileWatch create some tasks which are performed on message
+  // loop of BrowserThread::FILE. Wait until they are done.
+  content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
+  // We also wait the UI thread here, since some tasks which are performed above
+  // message loop back results to the UI thread.
   base::RunLoop().RunUntilIdle();
 
   // When /a is deleted (1 and 2 is notified).
   FileChange first_change;
   first_change.Update(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/a")),
       FileType::FILE_TYPE_DIRECTORY, ChangeType::CHANGE_TYPE_DELETE);
   event_router_->OnFileChanged(first_change);
   EXPECT_EQ(2, counter);
 
@@ skipping 17 matching lines @@
   event_router_->RemoveFileWatch(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/a/b/c")),
       "extension_1");
   event_router_->RemoveFileWatch(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/a/d/e")),
       "extension_2");
   event_router_->RemoveFileWatch(
       base::FilePath(FILE_PATH_LITERAL("/no-existing-fs/root/aaa")),
       "extension_3");
 
-  // event_router->addFileWatch create some tasks which are performed on
-  // TaskScheduler. Wait until they are done.
-  base::TaskScheduler::GetInstance()->FlushForTesting();
+  // event_router->removeFileWatch create some tasks which are performed on
+  // message loop of BrowserThread::FILE. Wait until they are done.
+  content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
 }
 
 IN_PROC_BROWSER_TEST_F(FileManagerPrivateApiTest, ContentChecksum) {
   base::ScopedTempDir temp_dir;
   base::FilePath mount_point_dir;
   const char kLocalMountPointName[] = "local";
 
   ASSERT_TRUE(InitializeLocalFileSystem(kLocalMountPointName, &temp_dir,
                                         &mount_point_dir))
       << "Failed to initialize test file system";
 
   EXPECT_TRUE(content::BrowserContext::GetMountPoints(browser()->profile())
                   ->RegisterFileSystem(
                       kLocalMountPointName, storage::kFileSystemTypeNativeLocal,
                       storage::FileSystemMountOption(), mount_point_dir));
   file_manager::VolumeManager::Get(browser()->profile())
       ->AddVolumeForTesting(mount_point_dir, file_manager::VOLUME_TYPE_TESTING,
                             chromeos::DEVICE_TYPE_UNKNOWN,
                             false /* read_only */);
 
   ASSERT_TRUE(RunComponentExtensionTest("file_browser/content_checksum_test"));
 }