Manage UsbService lifetime in DeviceClient implementations.

device/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//testing/test.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")  # For generate_jni().
 }
@@ skipping 93 matching lines @@
   if (use_udev) {
     sources += [ "udev_linux/udev_unittest.cc" ]
     deps += [ "//device/udev_linux" ]
   }
 
   # USB does not compile on mobile platforms.
   if (!is_android && !is_ios) {
     sources += [
       "devices_app/usb/device_impl_unittest.cc",
       "devices_app/usb/device_manager_impl_unittest.cc",
+      "test/test_device_client.cc",
+      "test/test_device_client.h",
       "test/usb_test_gadget_impl.cc",
       "usb/usb_context_unittest.cc",
       "usb/usb_descriptors_unittest.cc",
       "usb/usb_device_filter_unittest.cc",
       "usb/usb_device_handle_unittest.cc",
       "usb/usb_ids_unittest.cc",
       "usb/usb_service_unittest.cc",
       "usb/webusb_descriptors_unittest.cc",
     ]
     deps += [
@@ skipping 51 matching lines @@
   }
 
   android_library("bluetooth_test_java") {
     java_files = bluetooth_java_sources_needing_jni
     deps = [
       "//base:base_java",
       "//device/bluetooth:java",
     ]
   }
 }