Idletimer-related commands porting

Test: built, flashed, booted
      system/netd/tests/runtests.sh passes

Change-Id: I10eec44acca8e4d5a7c8de64b89590e3cccda597
diff --git a/server/NetdNativeService.h b/server/NetdNativeService.h
index 6ae5c89..3023f80 100644
--- a/server/NetdNativeService.h
+++ b/server/NetdNativeService.h
@@ -194,6 +194,12 @@
             int32_t oKey);
 
     binder::Status removeVirtualTunnelInterface(const std::string& deviceName);
+
+    // Idletimer-related commands
+    binder::Status idletimerAddInterface(const std::string& ifName, int32_t timeout,
+                                         const std::string& classLabel) override;
+    binder::Status idletimerRemoveInterface(const std::string& ifName, int32_t timeout,
+                                            const std::string& classLabel) override;
 };
 
 }  // namespace net