Code clean up

- Remove unused DashboardTilePreference class
- Use FooterPreference in ManageAssist fragment
- reformat manage_assist xml file

Bug: 35203386
Test: visual
Change-Id: If3dbbd0fb1977d6f3c7dbf4544d71f5e6e801327

src/com/android/settings/applications/ManageAssist.java

@@ -68,7 +68,8 @@ public class ManageAssist extends SettingsPreferenceFragment
 
         mFlashPref = (SwitchPreference) findPreference(KEY_FLASH);
         mFlashPref.setOnPreferenceChangeListener(this);
-
+        mFooterPreferenceMixin.createFooterPreference()
+                .setTitle(R.string.assist_footer);
         mVoiceInputPref = (VoiceInputListPreference) findPreference(KEY_VOICE_INPUT);
         updateUi();
     }

src/com/android/settings/dashboard/DashboardTilePreference.java

@@ -1,45 +0,0 @@
-/**
- * Copyright (C) 2016 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.dashboard;
-
-import android.content.Context;
-import android.util.AttributeSet;
-
-import com.android.settings.DividerPreference;
-import com.android.settings.R;
-
-/**
- * A {@code Preference} styled as a dashboard tile.
- */
-public class DashboardTilePreference extends DividerPreference {
-
-    public DashboardTilePreference(Context context, AttributeSet attrs) {
-        super(context, attrs);
-        init();
-    }
-
-    public DashboardTilePreference(Context context) {
-        super(context);
-        init();
-    }
-
-    private void init() {
-        setLayoutResource(R.layout.dashboard_tile);
-        setDividerAllowedAbove(false);
-        setDividerAllowedBelow(false);
-    }
-
-}