Add a new method in Sliceable.

We are making some Settings Slices public and some not so we can expose
more Settings Slices to Settings Search without worrying about privacy
and security concern. Hence, add this method to distinguish these two.

Bug: 141088937
Test: rebuild
Change-Id: I457802bb6472ec81a3dfb65c0674af4bb3dd4b5a

src/com/android/settings/slices/Sliceable.java

@@ -25,6 +25,8 @@ import android.content.IntentFilter;
 import android.net.Uri;
 import android.widget.Toast;
 
+import androidx.slice.Slice;
+
 import com.android.settings.R;
 
 /**
@@ -49,12 +51,23 @@ public interface Sliceable {
      * <p>
      * This does not guarantee the setting is available.
      *
-     * @return {@code true} if the controller should be used externally as a Slice.
+     * @return {@code true} if the controller should be used as a Slice.
      */
     default boolean isSliceable() {
         return false;
     }
 
+    /**
+     * Determines if the {@link Slice} should be public to other apps.
+     * This does not guarantee the setting is available.
+     *
+     * @return {@code true} if the controller should be used as a Slice, and is
+     * publicly visible to other apps.
+     */
+    default boolean isPublicSlice() {
+        return false;
+    }
+
     /**
      * Returns uri for this slice (if it's a slice).
      */