Move some slice related api out of BasePreferenceController

And share with CustomSliceable.

Bug: 121150258
Test: rebuild
Change-Id: Ia5aed9c156fb168c1f001da6e37f7f12f191b385

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

@@ -0,0 +1,58 @@
+/*
+ * 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.slices;
+
+import android.content.IntentFilter;
+
+/**
+ * A collection of API making a PreferenceController "sliceable"
+ */
+public interface Sliceable {
+    /**
+     * @return an {@link IntentFilter} that includes all broadcasts which can affect the state of
+     * this Setting.
+     */
+    default IntentFilter getIntentFilter() {
+        return null;
+    }
+
+    /**
+     * Determines if the controller should be used as a Slice.
+     * <p>
+     * Important criteria for a Slice are:
+     * - Must be secure
+     * - Must not be a privacy leak
+     * - Must be understandable as a stand-alone Setting.
+     * <p>
+     * This does not guarantee the setting is available.
+     *
+     * @return {@code true} if the controller should be used externally as a Slice.
+     */
+    default boolean isSliceable() {
+        return false;
+    }
+
+    /**
+     * @return {@code true} if the setting update asynchronously.
+     * <p>
+     * For example, a Wifi controller would return true, because it needs to update the radio
+     * and wait for it to turn on.
+     */
+    default boolean hasAsyncUpdate() {
+        return false;
+    }
+}