[CrOS Tether] Add the notion of a tether DeviceState.

chromeos/components/tether/active_host_network_state_updater_unittest.cc

 // Copyright 2017 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 "chromeos/components/tether/active_host_network_state_updater.h"
 
 #include <memory>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
@@ skipping 29 matching lines @@
 }  // namespace
 
 class ActiveHostNetworkStateUpdaterTest : public NetworkStateTest {
  protected:
   ActiveHostNetworkStateUpdaterTest() : NetworkStateTest() {}
   ~ActiveHostNetworkStateUpdaterTest() override {}
 
   void SetUp() override {
     DBusThreadManager::Initialize();
     NetworkStateTest::SetUp();
+    network_state_handler()->SetTetherTechnologyState(
+        NetworkStateHandler::TECHNOLOGY_ENABLED);
     SetUpTetherNetwork();
     SetUpWifiNetwork();
 
     fake_active_host_ = base::MakeUnique<FakeActiveHost>();
 
     updater_ = base::WrapUnique(new ActiveHostNetworkStateUpdater(
         fake_active_host_.get(), network_state_handler()));
   }
 
   void SetUpTetherNetwork() {
@@ skipping 57 matching lines @@
                                             kWifiNetworkGuid);
   VerifyConnected();
 
   fake_active_host_->SetActiveHostDisconnected();
   VerifyDisconnected();
 }
 
 }  // namespace tether
 
 }  // namespace chromeos