Add missing files in //device to appropriate BUILD.gn files.

device/battery/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
 # On android, BatteryManager mojo service is implemented directly in Java.
 if (!is_android) {
   component("battery") {
     output_name = "device_battery"
 
     sources = [
       "battery_export.h",
       "battery_monitor_impl.cc",
       "battery_monitor_impl.h",
+      "battery_status_manager.h",
       "battery_status_manager_chromeos.cc",
       "battery_status_manager_default.cc",
       "battery_status_manager_linux-inl.h",
       "battery_status_manager_linux.cc",
       "battery_status_manager_linux.h",
       "battery_status_manager_mac.cc",
       "battery_status_manager_win.cc",
       "battery_status_manager_win.h",
       "battery_status_service.cc",
       "battery_status_service.h",
@@ skipping 43 matching lines @@
     }
   }
 }
 
 mojom("mojo_bindings") {
   sources = [
     "battery_monitor.mojom",
     "battery_status.mojom",
   ]
 }