add skeleton CarServiceHelperService

- CarServiceHelperService is a companion service for car service which
  is used only for car product.
- HelperService starts car service and provide necessary interface
  for system server internal behavior control.

bug: 62342376
Test: test boot-up
Change-Id: I1728437434eab36bd2df6ba0a534731823bbcf35

services/java/com/android/server/SystemServer.java

@@ -63,6 +63,7 @@ import com.android.server.accessibility.AccessibilityManagerService;
 import com.android.server.am.ActivityManagerService;
 import com.android.server.audio.AudioService;
 import com.android.server.camera.CameraServiceProxy;
+import com.android.server.car.CarServiceHelperService;
 import com.android.server.clipboard.ClipboardService;
 import com.android.server.connectivity.IpConnectivityMetrics;
 import com.android.server.coverage.CoverageService;
@@ -1697,6 +1698,12 @@ public final class SystemServer {
                 }, WEBVIEW_PREPARATION);
             }
 
+            if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) {
+                traceBeginAndSlog("StartCarServiceHelperService");
+                mSystemServiceManager.startService(CarServiceHelperService.class);
+                traceEnd();
+            }
+
             traceBeginAndSlog("StartSystemUI");
             try {
                 startSystemUi(context, windowManagerF);