Ensure tests have an active task runner

chrome/browser/chromeos/system/device_disabling_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 "chrome/browser/chromeos/system/device_disabling_manager.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/memory/ref_counted.h"
@@ skipping 118 matching lines @@
 
   void CheckWhetherDeviceDisabledDuringOOBE();
 
   void SetDeviceDisabled(bool disabled);
 
  private:
   void OnDeviceDisabledChecked(bool device_disabled);
 
   TestingPrefServiceSimple local_state_;
 
+  content::TestBrowserThreadBundle thread_bundle_;
   base::RunLoop run_loop_;
   bool device_disabled_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceDisablingManagerOOBETest);
 };
 
 DeviceDisablingManagerOOBETest::DeviceDisablingManagerOOBETest()
     : device_disabled_(false) {
   EXPECT_CALL(*this, RestartToLoginScreen()).Times(0);
   EXPECT_CALL(*this, ShowDeviceDisabledScreen()).Times(0);
@@ skipping 357 matching lines @@
       DeviceDisablingManager::HonorDeviceDisablingDuringNormalOperation());
 
   // Not enterprise owned, disabled by flag.
   SetUnowned();
   EXPECT_FALSE(
       DeviceDisablingManager::HonorDeviceDisablingDuringNormalOperation());
 }
 
 }  // namespace system
 }  // namespace chromeos