Do no convert FaceSettingsAttention to slice.

The check logic of this preference requires a page loading prior to
slice auto convertion, so it is not suitable to become a slice.
Converting it to a slice will lead to an app crash.

Fixes: 145723632
Test: robotests
Change-Id: Ie6eafb244e9a1cc9267f6b747c8e357d239e688e

src/com/android/settings/biometrics/face/FaceSettingsAttentionPreferenceController.java

@@ -26,7 +26,6 @@ import androidx.preference.PreferenceScreen;
 import androidx.preference.SwitchPreference;
 
 import com.android.settings.Utils;
-import com.android.settings.core.TogglePreferenceController;
 
 /**
  * Preference controller that manages the ability to use face authentication with/without
@@ -117,6 +116,11 @@ public class FaceSettingsAttentionPreferenceController extends FaceSettingsPrefe
         return true;
     }
 
+    @Override
+    public boolean isSliceable() {
+        return false;
+    }
+
     @Override
     public int getAvailabilityStatus() {
         return AVAILABLE;

tests/robotests/src/com/android/settings/biometrics/face/FaceSettingsAttentionPreferenceControllerTest.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.biometrics.face;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class FaceSettingsAttentionPreferenceControllerTest {
+
+    private Context mContext;
+    private FaceSettingsAttentionPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mController = new FaceSettingsAttentionPreferenceController(mContext);
+    }
+
+    @Test
+    public void isSliceable_returnFalse() {
+        assertThat(mController.isSliceable()).isFalse();
+    }
+}