[SyncFS] Remove unneeded #include from sync_task_manager.h

chrome/browser/sync_file_system/drive_backend/sync_task_manager_unittest.cc

 // Copyright 2014 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 <deque>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
+#include "chrome/browser/sync_file_system/drive_backend/sync_task.h"
 #include "chrome/browser/sync_file_system/drive_backend/sync_task_manager.h"
 #include "chrome/browser/sync_file_system/drive_backend/sync_task_token.h"
 #include "chrome/browser/sync_file_system/sync_file_system_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webkit/common/fileapi/file_system_util.h"
 
 #define MAKE_PATH(path)                                       \
   base::FilePath(fileapi::VirtualPath::GetNormalizedFilePath( \
       base::FilePath(FILE_PATH_LITERAL(path))))
 
@@ skipping 630 matching lines @@
 
   EXPECT_EQ("task1: finished", log[i++]);
 
   EXPECT_EQ("task2: updating to /hoge/fuga/piyo", log[i++]);
   EXPECT_EQ("task2: updated to /hoge/fuga/piyo", log[i++]);
   EXPECT_EQ("task2: finished", log[i++]);
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system