[SyncFS] Make SyncEngineInitializer run as a background task (3/3)

chrome/browser/sync_file_system/drive_backend/conflict_resolver_unittest.cc

 // Copyright 2013 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/sync_file_system/drive_backend/conflict_resolver.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 76 matching lines @@
 
     RevokeSyncableFileSystem();
 
     fake_remote_change_processor_.reset();
     fake_drive_helper_.reset();
     context_.reset();
     base::RunLoop().RunUntilIdle();
   }
 
   void InitializeMetadataDatabase() {
-    SyncEngineInitializer initializer(context_.get(),
-                                      base::MessageLoopProxy::current(),
-                                      context_->GetDriveService(),
-                                      database_dir_.path(),
-                                      in_memory_env_.get());
+    SyncEngineInitializer* initializer =
+        new SyncEngineInitializer(context_.get(),
+                                  base::MessageLoopProxy::current(),
+                                  context_->GetDriveService(),
+                                  database_dir_.path(),
+                                  in_memory_env_.get());
     SyncStatusCode status = SYNC_STATUS_UNKNOWN;
-    initializer.RunSequential(CreateResultReceiver(&status));
+    sync_task_manager_->ScheduleSyncTask(
+        FROM_HERE,
+        scoped_ptr<SyncTask>(initializer),
+        SyncTaskManager::PRIORITY_MED,
+        base::Bind(&ConflictResolverTest::DidInitializeMetadataDatabase,
+                   base::Unretained(this), initializer, &status));
+
     base::RunLoop().RunUntilIdle();
     EXPECT_EQ(SYNC_STATUS_OK, status);
-    context_->SetMetadataDatabase(initializer.PassMetadataDatabase());
+  }
+
+  void DidInitializeMetadataDatabase(SyncEngineInitializer* initializer,
+                                     SyncStatusCode* status_out,
+                                     SyncStatusCode status) {
+    context_->SetMetadataDatabase(initializer->PassMetadataDatabase());
+    *status_out = status;
   }
 
   void RegisterApp(const std::string& app_id,
                    const std::string& app_root_folder_id) {
     SyncStatusCode status = SYNC_STATUS_FAILED;
     context_->GetMetadataDatabase()->RegisterApp(app_id, app_root_folder_id,
                                                  CreateResultReceiver(&status));
     base::RunLoop().RunUntilIdle();
     EXPECT_EQ(SYNC_STATUS_OK, status);
   }
@@ skipping 387 matching lines @@
 
   EXPECT_EQ(4, CountParents(file));
 
   EXPECT_EQ(SYNC_STATUS_OK, RunConflictResolver());
 
   EXPECT_EQ(1, CountParents(file));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system