Introduce ThreadTaskRunnerHandle::OverrideForTesting and TestMockTimeTaskRunner::ScopedContext.

chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos_unittest.cc

 // Copyright (c) 2012 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/policy/device_cloud_policy_manager_chromeos.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 95 matching lines @@
 
   ~TestingDeviceCloudPolicyManagerChromeOS() override {}
 };
 
 class DeviceCloudPolicyManagerChromeOSTest
     : public chromeos::DeviceSettingsTestBase,
       public DeviceCloudPolicyManagerChromeOS::Observer {
  protected:
   DeviceCloudPolicyManagerChromeOSTest()
       : fake_cryptohome_client_(new chromeos::FakeCryptohomeClient()),
-        state_keys_broker_(&fake_session_manager_client_,
-                           base::ThreadTaskRunnerHandle::Get()),
+        state_keys_broker_(&fake_session_manager_client_),
         store_(NULL) {
     fake_statistics_provider_.SetMachineStatistic(
         chromeos::system::kSerialNumberKey, "test_sn");
     fake_statistics_provider_.SetMachineStatistic(
         chromeos::system::kHardwareClassKey, "test_hw");
     std::vector<std::string> state_keys;
     state_keys.push_back("1");
     state_keys.push_back("2");
     state_keys.push_back("3");
     fake_session_manager_client_.set_server_backed_state_keys(state_keys);
@@ skipping 694 matching lines @@
                         DeviceCloudPolicyManagerChromeOSEnrollmentTest,
                         ::testing::Values(false, true));
 
 INSTANTIATE_TEST_CASE_P(
     Cert,
     DeviceCloudPolicyManagerChromeOSEnrollmentBlankSystemSaltTest,
     ::testing::Values(false, true));
 
 }  // namespace
 }  // namespace policy