Define NOT_ROAMING network capability.

The "roaming" state of a network really belongs on NetworkCapabilities
instead of being published through NetworkInfo.isRoaming().  One major
reason is to support developers creating NetworkRequests for a
non-roaming network.

Test: bit FrameworksNetTests:android.net.,com.android.server.net.
Bug: 68397798, 16207332
Change-Id: Id115bd88c3a83462dfececb145e9d1900ee0a8a6
diff --git a/service/java/com/android/server/wifi/WifiStateMachine.java b/service/java/com/android/server/wifi/WifiStateMachine.java
index 66ab1a3..a8bd578 100644
--- a/service/java/com/android/server/wifi/WifiStateMachine.java
+++ b/service/java/com/android/server/wifi/WifiStateMachine.java
@@ -977,6 +977,7 @@
         mNetworkCapabilitiesFilter.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
         mNetworkCapabilitiesFilter.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET);
         mNetworkCapabilitiesFilter.addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_METERED);
+        mNetworkCapabilitiesFilter.addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_ROAMING);
         mNetworkCapabilitiesFilter.addCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED);
         mNetworkCapabilitiesFilter.setLinkUpstreamBandwidthKbps(1024 * 1024);
         mNetworkCapabilitiesFilter.setLinkDownstreamBandwidthKbps(1024 * 1024);