Blocked packages can't create channels.

Test: runtest systemui-notification
Change-Id: I3f0560a71adc33d9881021f920ce2824b96ddc14

services/core/java/com/android/server/notification/RankingHelper.java

@@ -15,6 +15,8 @@
  */
 package com.android.server.notification;
 
+import static android.app.NotificationManager.IMPORTANCE_NONE;
+
 import com.android.internal.R;
 
 import android.app.Notification;
@@ -450,6 +452,9 @@ public class RankingHelper implements RankingConfig {
     @Override
     public void createNotificationChannel(String pkg, int uid, NotificationChannel channel) {
         Record r = getOrCreateRecord(pkg, uid);
+        if (IMPORTANCE_NONE == r.importance) {
+            throw new IllegalArgumentException("Package blocked");
+        }
         if (r.channels.containsKey(channel.getId()) || channel.getName().equals(
                 mContext.getString(R.string.default_notification_channel_label))) {
             throw new IllegalArgumentException("Channel already exists");

services/tests/notification/src/com/android/server/notification/RankingHelperTest.java

@@ -15,6 +15,8 @@
  */
 package com.android.server.notification;
 
+import static junit.framework.Assert.fail;
+
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -347,6 +349,19 @@ public class RankingHelperTest {
         assertEquals(NotificationChannel.USER_LOCKED_VISIBILITY, updated2.getUserLockedFields());
     }
 
+    @Test
+    public void testCreateChannel_blocked() throws Exception {
+        mHelper.setImportance(pkg, uid, NotificationManager.IMPORTANCE_NONE);
+
+        try {
+            mHelper.createNotificationChannel(pkg, uid,
+                    new NotificationChannel(pkg, "", NotificationManager.IMPORTANCE_LOW));
+            fail("Channel creation should fail");
+        } catch (IllegalArgumentException e) {
+            // pass
+        }
+    }
+
     @Test
     public void testUpdate_userLockedImportance() throws Exception {
         // all fields locked by user