Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

ui/accessibility/platform/atk_util_auralinux.cc

 // Copyright 2015 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 <atk/atk.h>
 #if defined(USE_GCONF)
 #include <gconf/gconf-client.h>
 #endif
 #include <glib-2.0/gmodule.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/singleton.h"
+#include "base/task_runner.h"
 #include "ui/accessibility/platform/atk_util_auralinux.h"
 #include "ui/accessibility/platform/ax_platform_node_auralinux.h"
 
 namespace {
 
 typedef void (*gnome_accessibility_module_init)();
 
 const char kAtkBridgePath[] = "gtk-2.0/modules/libatk-bridge.so";
 const char kAtkBridgeSymbolName[] = "gnome_accessibility_module_init";
 
@@ skipping 211 matching lines @@
 
 void AtkUtilAuraLinux::CheckIfAccessibilityIsEnabledOnFileThread() {
 }
 
 void AtkUtilAuraLinux::FinishAccessibilityInitOnUIThread() {
 }
 
 #endif // defined(USE_GCONF)
 
 }  // namespace ui