Allow unexported receiver registration for sandbox

Webview uses some system level broadcasts. This change
enables webview to work in the sandbox process
Bug: b/226564146
Test: Manual

Change-Id: I8b1a51c513b825e6749d1b711d6ef0b9f13300af

services/core/java/com/android/server/am/ActivityManagerService.java

@@ -12938,7 +12938,12 @@ public class ActivityManagerService extends IActivityManager.Stub
     public Intent registerReceiverWithFeature(IApplicationThread caller, String callerPackage,
             String callerFeatureId, String receiverId, IIntentReceiver receiver,
             IntentFilter filter, String permission, int userId, int flags) {
-        enforceNotIsolatedOrSdkSandboxCaller("registerReceiver");
+        // Allow Sandbox process to register only unexported receivers.
+        if ((flags & Context.RECEIVER_NOT_EXPORTED) != 0) {
+            enforceNotIsolatedCaller("registerReceiver");
+        } else {
+            enforceNotIsolatedOrSdkSandboxCaller("registerReceiver");
+        }
         ArrayList<Intent> stickyIntents = null;
         ProcessRecord callerApp = null;
         final boolean visibleToInstantApps