Remove FILE thread from sync_file_system tests

This CL removes all dependencies to BrowserThread::FILE in sync_file_system,
and replaces them with base/task_scheduler's ones.

Change-Id: Idd3ffb66d2d3079f3b6b680bde8b016d696ce268
Reviewed-on: https://chromium-review.googlesource.com/575735
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487456}

chrome/browser/sync_file_system/drive_backend/drive_backend_sync_unittest.cc

@@ -93,8 +93,7 @@ class DriveBackendSyncTest : public testing::Test,
         content::BrowserThread::IO);
     worker_task_runner_ = base::CreateSequencedTaskRunnerWithTraits(
         {base::MayBlock(), base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
-    file_task_runner_ = content::BrowserThread::GetTaskRunnerForThread(
-        content::BrowserThread::FILE);
+    file_task_runner_ = io_task_runner_;
     scoped_refptr<base::SequencedTaskRunner> drive_task_runner =
         base::CreateSequencedTaskRunnerWithTraits(
             {base::MayBlock(), base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});

chrome/browser/sync_file_system/local/local_file_sync_context_unittest.cc

@@ -59,9 +59,7 @@ const char kOrigin2[] = "http://chromium.org";
 class LocalFileSyncContextTest : public testing::Test {
  protected:
   LocalFileSyncContextTest()
-      : thread_bundle_(
-            content::TestBrowserThreadBundle::REAL_FILE_THREAD |
-            content::TestBrowserThreadBundle::REAL_IO_THREAD),
+      : thread_bundle_(content::TestBrowserThreadBundle::REAL_IO_THREAD),
         status_(SYNC_FILE_ERROR_FAILED),
         file_error_(base::File::FILE_ERROR_FAILED),
         async_modify_finished_(false),

chrome/browser/sync_file_system/local/local_file_sync_service_unittest.cc

@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/stl_util.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
@@ -108,8 +109,7 @@ class LocalFileSyncServiceTest
       public LocalFileSyncService::Observer {
  protected:
   LocalFileSyncServiceTest()
-      : thread_bundle_(content::TestBrowserThreadBundle::REAL_FILE_THREAD |
-                       content::TestBrowserThreadBundle::REAL_IO_THREAD),
+      : thread_bundle_(content::TestBrowserThreadBundle::REAL_IO_THREAD),
         num_changes_(0) {}
 
   void SetUp() override {
@@ -119,7 +119,7 @@ class LocalFileSyncServiceTest
     file_system_.reset(new CannedSyncableFileSystem(
         GURL(kOrigin), in_memory_env_.get(),
         BrowserThread::GetTaskRunnerForThread(BrowserThread::IO),
-        BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE)));
+        base::CreateSingleThreadTaskRunnerWithTraits({base::MayBlock()})));
 
     local_service_ = LocalFileSyncService::CreateForTesting(
         &profile_, in_memory_env_.get());
@@ -145,7 +145,8 @@ class LocalFileSyncServiceTest
     local_service_->Shutdown();
     file_system_->TearDown();
     RevokeSyncableFileSystem();
-    content::RunAllPendingInMessageLoop(BrowserThread::FILE);
+
+    base::TaskScheduler::GetInstance()->FlushForTesting();
     content::RunAllPendingInMessageLoop(BrowserThread::IO);
   }
 
@@ -301,7 +302,7 @@ TEST_F(LocalFileSyncServiceTest, MAYBE_LocalChangeObserverMultipleContexts) {
   CannedSyncableFileSystem file_system2(
       GURL(kOrigin2), in_memory_env_.get(),
       BrowserThread::GetTaskRunnerForThread(BrowserThread::IO),
-      BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE));
+      base::CreateSingleThreadTaskRunnerWithTraits({base::MayBlock()}));
   file_system2.SetUp(CannedSyncableFileSystem::QUOTA_ENABLED);
 
   base::RunLoop run_loop;

chrome/browser/sync_file_system/sync_file_system_service_unittest.cc

@@ -13,6 +13,7 @@
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/synchronization/waitable_event.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/sync_file_system/local/canned_syncable_file_system.h"
 #include "chrome/browser/sync_file_system/local/local_file_sync_context.h"
@@ -128,15 +129,14 @@ ACTION(InvokeCompletionClosure) {
 class SyncFileSystemServiceTest : public testing::Test {
  protected:
   SyncFileSystemServiceTest()
-      : thread_bundle_(content::TestBrowserThreadBundle::REAL_FILE_THREAD |
-                       content::TestBrowserThreadBundle::REAL_IO_THREAD) {}
+      : thread_bundle_(content::TestBrowserThreadBundle::REAL_IO_THREAD) {}
 
   void SetUp() override {
     in_memory_env_.reset(leveldb::NewMemEnv(leveldb::Env::Default()));
     file_system_.reset(new CannedSyncableFileSystem(
         GURL(kOrigin), in_memory_env_.get(),
         BrowserThread::GetTaskRunnerForThread(BrowserThread::IO),
-        BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE)));
+        base::CreateSingleThreadTaskRunnerWithTraits({base::MayBlock()})));
 
     std::unique_ptr<LocalFileSyncService> local_service =
         LocalFileSyncService::CreateForTesting(&profile_, in_memory_env_.get());
@@ -168,7 +168,7 @@ class SyncFileSystemServiceTest : public testing::Test {
     sync_service_->Shutdown();
     file_system_->TearDown();
     RevokeSyncableFileSystem();
-    content::RunAllPendingInMessageLoop(BrowserThread::FILE);
+    base::TaskScheduler::GetInstance()->FlushForTesting();
   }
 
   void InitializeApp() {