给系统添加服务定制标准api
1.在frameworks/base/services/core/java/com/android/server/ 下添加相关的service
2.在SystemServiceRegistry.java(frameworks/base/core/java/android/app/)里注册这个服务
3.在SystemServer.java(frameworks/base/services/core/java/com/android/server/ )里启动这个服务
4.在Context.java(frameworks/base/core/java/android/content/)里添加
5.添加系统api,system/sepolicy/prebuilts/api/26-31/(private/service_contexts/public/service.te)
直接全编会报错,先执行:make api-stubs-docs-non-updatable-update-current-api
