packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java

/frameworks/base/telephony/java/android/telephony/SubscriptionManager.java

frameworks/ base/telephony/java/android/telephony/CarrierConfigManager.java

===========附上：默认开启或关闭数据流量

SettingsProvider\src\com\android\providers\settings\DatabaseHelper.java