Add Slider template for Slices

Add the Seekbar preference equivalent
to the TwoStatePreference (toggle) preference
controller abstract controller.

Change-Id: I6ff91f2f72a7f72c18ddbc27b2b1fda4b6ce6ca9
Fixes: 67996707
Test: Robotests

tests/robotests/src/com/android/settings/testutils/FakeSliderController.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2018 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.testutils;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import com.android.settings.core.BasePreferenceController;
+import com.android.settings.core.SliderPreferenceController;
+
+public class FakeSliderController extends SliderPreferenceController {
+
+    private final String settingKey = "fake_slider_key";
+
+    public static final int MAX_STEPS = 9;
+
+    public FakeSliderController(Context context, String key) {
+        super(context, key);
+    }
+
+    @Override
+    public int getSliderPosition() {
+        return Settings.System.getInt(mContext.getContentResolver(), settingKey, 0);
+    }
+
+    @Override
+    public boolean setSliderPosition(int position) {
+        return Settings.System.putInt(mContext.getContentResolver(), settingKey, position);
+    }
+
+    @Override
+    public int getMaxSteps() {
+        return MAX_STEPS;
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return BasePreferenceController.AVAILABLE;
+    }
+}