New receiver for signed config.

A new receiver is added when the system server is created. It receives
broadcasts and pulls out the config & signature, but doesn't yet do
anything with it.

go/serverless-config-design
Test: Manual
Bug: 110509075

Change-Id: Ie369e198de5e830253b17e964afb67c76735909c

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

@@ -121,6 +121,7 @@ import com.android.server.restrictions.RestrictionsManagerService;
 import com.android.server.role.RoleManagerService;
 import com.android.server.security.KeyAttestationApplicationIdProviderService;
 import com.android.server.security.KeyChainSystemService;
+import com.android.server.signedconfig.SignedConfigService;
 import com.android.server.soundtrigger.SoundTriggerService;
 import com.android.server.stats.StatsCompanionService;
 import com.android.server.statusbar.StatusBarManagerService;
@@ -1003,6 +1004,11 @@ public final class SystemServer {
             traceBeginAndSlog("PinnerService");
             mSystemServiceManager.startService(PinnerService.class);
             traceEnd();
+
+            traceBeginAndSlog("SignedConfigService");
+            SignedConfigService.registerUpdateReceiver(mSystemContext);
+            traceEnd();
+
         } catch (RuntimeException e) {
             Slog.e("System", "******************************************");
             Slog.e("System", "************ Failure starting core service", e);