Merge "Migrate away from AsyncChannel in NetworkAgent"

Android.bp

core/java/android/net/ConnectivityManager.java

core/java/android/net/IConnectivityManager.aidl

core/java/android/net/NattKeepalivePacketData.aidl

core/java/android/net/NetworkAgent.java

core/java/android/net/TcpKeepalivePacketData.aidl

...ces/core/java/com/android/server/ConnectivityService.java

...ava/com/android/server/connectivity/KeepaliveTracker.java

...ava/com/android/server/connectivity/NetworkAgentInfo.java

.../net/java/com/android/server/ConnectivityServiceTest.java

...va/com/android/server/connectivity/LingerMonitorTest.java