Dump notification dot counts

This could help us determine whether our data model or
UI is wrong if dots aren't appearing.

Bug: 152435463
Change-Id: I46065b130b6b1cbb3b2d1db471654b3959332ff5
diff --git a/src/com/android/launcher3/util/PackageUserKey.java b/src/com/android/launcher3/util/PackageUserKey.java
index 46e7070..3a3b5a2 100644
--- a/src/com/android/launcher3/util/PackageUserKey.java
+++ b/src/com/android/launcher3/util/PackageUserKey.java
@@ -3,6 +3,7 @@
 import android.os.UserHandle;
 import android.service.notification.StatusBarNotification;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
 import com.android.launcher3.model.data.ItemInfo;
@@ -60,4 +61,10 @@
         PackageUserKey otherKey = (PackageUserKey) obj;
         return mPackageName.equals(otherKey.mPackageName) && mUser.equals(otherKey.mUser);
     }
+
+    @NonNull
+    @Override
+    public String toString() {
+        return mPackageName + "#" + mUser;
+    }
 }