Split out the ethernet API surface and use framework-connectivity-t

Ethernet framework and service source code is going to be moved to
Connectivity mainline module, this CL contains below corresponding
changes to adapt the migration in f/b side:

1. Split out ethernet module-lib APIs to Connectivity module.
   Add the ethernet resource filegroup to tiramisu-updatable-sources
   filegroup as well, build them together. Also update the module-lib
   and system api txt to reflect the APIs change. Remove the hidden
   APIs which are moved to Connectivity module. This removal fixes the
   api inconsistent issue with Tethering/apex/hidden/.

2. Remove EthernetService from SystemServer which will be registered
   from ConnectivityServiceInitializer.

3. Replace the BackgroundThread class(imported from f/b/core/java)
   with the one in the modules-utils-backgroundthread lib, which is
   visible to Connectivity module.

Bug: 210586283
Test: m
Test: atest FrameworksNetTests EthernetServiceTests
Change-Id: I3e13cb9c0e348333af295c2537d459aa6700ff17
Merged-In: I1956848d3248cc56e9841d221e5e4c160bed65a4
diff --git a/framework-t/Sources.bp b/framework-t/Sources.bp
index 6652780..217a1f6 100644
--- a/framework-t/Sources.bp
+++ b/framework-t/Sources.bp
@@ -154,17 +154,17 @@
     ],
 }
 
+// TODO: remove this empty filegroup.
 filegroup {
     name: "framework-connectivity-tiramisu-sources",
-    srcs: [
-        ":framework-connectivity-ethernet-sources",
-    ],
+    srcs: [],
     visibility: ["//frameworks/base"],
 }
 
 filegroup {
     name: "framework-connectivity-tiramisu-updatable-sources",
     srcs: [
+        ":framework-connectivity-ethernet-sources",
         ":framework-connectivity-ipsec-sources",
         ":framework-connectivity-netstats-sources",
         ":framework-connectivity-nsd-sources",
diff --git a/framework-t/src/android/net/ConnectivityFrameworkInitializerTiramisu.java b/framework-t/src/android/net/ConnectivityFrameworkInitializerTiramisu.java
index 9bffbfb..61b34d0 100644
--- a/framework-t/src/android/net/ConnectivityFrameworkInitializerTiramisu.java
+++ b/framework-t/src/android/net/ConnectivityFrameworkInitializerTiramisu.java
@@ -34,8 +34,9 @@
     private ConnectivityFrameworkInitializerTiramisu() {}
 
     /**
-     * Called by {@link SystemServiceRegistry}'s static initializer and registers nsd services to
-     * {@link Context}, so that {@link Context#getSystemService} can return them.
+     * Called by {@link SystemServiceRegistry}'s static initializer and registers NetworkStats, nsd,
+     * ipsec and ethernet services to {@link Context}, so that {@link Context#getSystemService} can
+     * return them.
      *
      * @throws IllegalStateException if this is called anywhere besides
      * {@link SystemServiceRegistry}.
@@ -68,5 +69,14 @@
                     return new NetworkStatsManager(context, service);
                 }
         );
+
+        SystemServiceRegistry.registerContextAwareService(
+                Context.ETHERNET_SERVICE,
+                EthernetManager.class,
+                (context, serviceBinder) -> {
+                    IEthernetManager service = IEthernetManager.Stub.asInterface(serviceBinder);
+                    return new EthernetManager(context, service);
+                }
+        );
     }
 }
diff --git a/framework-t/src/android/net/EthernetManager.java b/framework-t/src/android/net/EthernetManager.java
index eba51c1..793f28d 100644
--- a/framework-t/src/android/net/EthernetManager.java
+++ b/framework-t/src/android/net/EthernetManager.java
@@ -33,7 +33,7 @@
 import android.os.RemoteException;
 
 import com.android.internal.annotations.GuardedBy;
-import com.android.internal.os.BackgroundThread;
+import com.android.modules.utils.BackgroundThread;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;