Add getInterfaceList module-lib API in EthernetManager.

Bug: 171872016
Test: m
Change-Id: Ib0e6c8f67c6ded7d17bb9e0ff49e7ff495c8819d

packages/ConnectivityT/framework-t/src/android/net/EthernetManager.java

@@ -39,6 +39,7 @@ import com.android.modules.utils.BackgroundThread;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
+import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.Executor;
 import java.util.function.IntConsumer;
@@ -712,4 +713,20 @@ public class EthernetManager {
             maybeRemoveServiceListener();
         }
     }
+
+    /**
+     * Returns an array of existing Ethernet interface names regardless whether the interface
+     * is available or not currently.
+     * @hide
+     */
+    @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
+    @SystemApi(client = MODULE_LIBRARIES)
+    @NonNull
+    public List<String> getInterfaceList() {
+        try {
+            return mService.getInterfaceList();
+        } catch (RemoteException e) {
+            throw e.rethrowAsRuntimeException();
+        }
+    }
 }

packages/ConnectivityT/framework-t/src/android/net/IEthernetManager.aidl

@@ -23,6 +23,8 @@ import android.net.EthernetNetworkUpdateRequest;
 import android.net.INetworkInterfaceOutcomeReceiver;
 import android.net.ITetheredInterfaceCallback;
 
+import java.util.List;
+
 /**
  * Interface that answers queries about, and allows changing
  * ethernet configuration.
@@ -44,4 +46,5 @@ interface IEthernetManager
     void connectNetwork(String iface, in INetworkInterfaceOutcomeReceiver listener);
     void disconnectNetwork(String iface, in INetworkInterfaceOutcomeReceiver listener);
     void setEthernetEnabled(boolean enabled);
+    List<String> getInterfaceList();
 }