Make Ethernet interfaces more testable.

This CL adds a setIncludeTestInterfaces method to EthernetManager
that, when called, causes the Ethernet service to recognize and
manage test interfaces created by TestNetworkManager.

Bug: 150644681
Test: Tested by EthernetTetheringTest in same topic
Change-Id: I86eef7a93267f800dbfc8eafd307effa76a344ca

core/java/android/net/EthernetManager.java

@@ -199,6 +199,21 @@ public class EthernetManager {
         }
     }
 
+    /**
+     * Whether to treat interfaces created by {@link TestNetworkManager#createTapInterface}
+     * as Ethernet interfaces. The effects of this method apply to any test interfaces that are
+     * already present on the system.
+     * @hide
+     */
+    @TestApi
+    public void setIncludeTestInterfaces(boolean include) {
+        try {
+            mService.setIncludeTestInterfaces(include);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
     /**
      * A request for a tethered interface.
      */

core/java/android/net/IEthernetManager.aidl

@@ -33,6 +33,7 @@ interface IEthernetManager
     boolean isAvailable(String iface);
     void addListener(in IEthernetServiceListener listener);
     void removeListener(in IEthernetServiceListener listener);
+    void setIncludeTestInterfaces(boolean include);
     void requestTetheredInterface(in ITetheredInterfaceCallback callback);
     void releaseTetheredInterface(in ITetheredInterfaceCallback callback);
 }