Fix crash when starting daydream setting with wrong context

The context must be a UI context. This is a new requirement in P.

(Also converted the CurrentDream controller to be slice compatible)

Change-Id: I28874f296da617f4cedf6706b0663b76671f1780
Fixes: 111375261
Test: robotests

res/xml/dream_fragment_overview.xml

@@ -16,13 +16,15 @@
 
 <PreferenceScreen
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:settings="http://schemas.android.com/apk/res-auto"
     android:key="dream_overview_screen"
     android:title="@string/screensaver_settings_title">
 
     <com.android.settings.widget.GearPreference
         android:key="current_screensaver"
         android:title="@string/screensaver_settings_current"
-        android:fragment="com.android.settings.dream.CurrentDreamPicker" />
+        android:fragment="com.android.settings.dream.CurrentDreamPicker"
+        settings:controller="com.android.settings.dream.CurrentDreamPreferenceController" />
 
     <Preference
         android:key="when_to_start"

src/com/android/settings/dream/CurrentDreamPreferenceController.java

@@ -18,9 +18,8 @@ package com.android.settings.dream;
 
 import android.content.Context;
 
-import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settings.core.BasePreferenceController;
 import com.android.settings.widget.GearPreference;
-import com.android.settingslib.core.AbstractPreferenceController;
 import com.android.settingslib.dream.DreamBackend;
 import com.android.settingslib.dream.DreamBackend.DreamInfo;
 
@@ -28,40 +27,38 @@ import java.util.Optional;
 
 import androidx.preference.Preference;
 
-public class CurrentDreamPreferenceController extends AbstractPreferenceController implements
-        PreferenceControllerMixin {
-    private final DreamBackend mBackend;
-    private final static String TAG = "CurrentDreamPreferenceController";
-    private final static String CURRENT_SCREENSAVER = "current_screensaver";
+public class CurrentDreamPreferenceController extends BasePreferenceController {
 
-    public CurrentDreamPreferenceController(Context context) {
-        super(context);
+    private final DreamBackend mBackend;
+
+    public CurrentDreamPreferenceController(Context context, String key) {
+        super(context, key);
         mBackend = DreamBackend.getInstance(context);
     }
 
     @Override
-    public boolean isAvailable() {
-        return mBackend.getDreamInfos().size() > 0;
-    }
-
-    @Override
-    public String getPreferenceKey() {
-        return CURRENT_SCREENSAVER;
+    public int getAvailabilityStatus() {
+        return mBackend.getDreamInfos().size() > 0 ? AVAILABLE : CONDITIONALLY_UNAVAILABLE;
     }
 
     @Override
     public void updateState(Preference preference) {
         super.updateState(preference);
-
-        preference.setSummary(mBackend.getActiveDreamName());
         setGearClickListenerForPreference(preference);
     }
 
-    private void setGearClickListenerForPreference(Preference preference) {
-        if (!(preference instanceof GearPreference)) return;
+    @Override
+    public CharSequence getSummary() {
+        return mBackend.getActiveDreamName();
+    }
 
-        GearPreference gearPreference = (GearPreference)preference;
-        Optional<DreamInfo> info = getActiveDreamInfo();
+    private void setGearClickListenerForPreference(Preference preference) {
+        if (!(preference instanceof GearPreference)) {
+            return;
+        }
+
+        final GearPreference gearPreference = (GearPreference) preference;
+        final Optional<DreamInfo> info = getActiveDreamInfo();
         if (!info.isPresent() || info.get().settingsComponentName == null) {
             gearPreference.setOnGearClickListener(null);
             return;
@@ -70,9 +67,9 @@ public class CurrentDreamPreferenceController extends AbstractPreferenceControll
     }
 
     private void launchScreenSaverSettings() {
-        Optional<DreamInfo> info = getActiveDreamInfo();
+        final Optional<DreamInfo> info = getActiveDreamInfo();
         if (!info.isPresent()) return;
-        mBackend.launchSettings(info.get());
+        mBackend.launchSettings(mContext, info.get());
     }
 
     private Optional<DreamInfo> getActiveDreamInfo() {

src/com/android/settings/dream/DreamSettings.java

@@ -132,7 +132,6 @@ public class DreamSettings extends DashboardFragment {
 
     private static List<AbstractPreferenceController> buildPreferenceControllers(Context context) {
         List<AbstractPreferenceController> controllers = new ArrayList<>();
-        controllers.add(new CurrentDreamPreferenceController(context));
         controllers.add(new WhenToDreamPreferenceController(context));
         controllers.add(new StartNowPreferenceController(context));
         return controllers;

tests/robotests/src/com/android/settings/dream/CurrentDreamPreferenceControllerTest.java

@@ -56,7 +56,7 @@ public class CurrentDreamPreferenceControllerTest {
     public void setup() {
         MockitoAnnotations.initMocks(this);
 
-        mController = new CurrentDreamPreferenceController(mContext);
+        mController = new CurrentDreamPreferenceController(mContext, "test");
         ReflectionHelpers.setField(mController, "mBackend", mBackend);
     }