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

chromeos/components/tether/host_scanner_unittest.cc

 // Copyright 2016 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/host_scanner.h"
 
 #include <algorithm>
 #include <memory>
 #include <vector>
 
@@ skipping 121 matching lines @@
 class HostScannerTest : public NetworkStateTest {
  protected:
   HostScannerTest()
       : test_devices_(cryptauth::GenerateTestRemoteDevices(4)),
         test_scanned_device_infos(CreateFakeScannedDeviceInfos(test_devices_)) {
   }
 
   void SetUp() override {
     DBusThreadManager::Initialize();
     NetworkStateTest::SetUp();
+    network_state_handler()->SetTetherTechnologyState(
+        NetworkStateHandler::TECHNOLOGY_ENABLED);
 
     scanned_device_infos_so_far_.clear();
 
     fake_tether_host_fetcher_ = base::MakeUnique<FakeTetherHostFetcher>(
         test_devices_, false /* synchronously_reply_with_results */);
     fake_ble_connection_manager_ = base::MakeUnique<FakeBleConnectionManager>();
     fake_host_scan_device_prioritizer_ =
         base::MakeUnique<FakeHostScanDevicePrioritizer>();
     fake_notification_presenter_ =
         base::MakeUnique<FakeNotificationPresenter>();
@@ skipping 206 matching lines @@
       ->SendScannedDeviceListUpdate(scanned_device_infos_so_far_,
                                     true /* is_final_scan_result */);
   EXPECT_EQ(scanned_device_infos_so_far_,
             host_scanner_->most_recent_scan_results());
   EXPECT_FALSE(host_scanner_->IsScanActive());
 }
 
 }  // namespace tether
 
 }  // namespace chromeos