Add temporary link to PermissionController for new default apps UI.

This change adds a temporary link in the default apps settings to
allow launching the new default apps UI in PermissionController during
the process we migrate default apps to use roles.

Bug: 110557011
Test: manually tested the UI
Change-Id: I0ac340acd5a077c74b48b28c97f517adb2084a36

src/com/android/settings/applications/defaultapps/RolesPreferenceController.java

@@ -0,0 +1,62 @@
+/*
+ * 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.applications.defaultapps;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.provider.Settings;
+import android.text.TextUtils;
+
+import androidx.preference.Preference;
+
+import com.android.settings.core.BasePreferenceController;
+
+/**
+ * STOPSHIP(b/110557011): Remove once the new UI is ready.
+ */
+public class RolesPreferenceController extends BasePreferenceController {
+
+    private Intent mIntent;
+
+    public RolesPreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+
+        PackageManager packageManager = context.getPackageManager();
+        String packageName = packageManager.getPermissionControllerPackageName();
+        if (packageName != null) {
+            mIntent = new Intent(Settings.ACTION_MANAGE_DEFAULT_APPS_SETTINGS)
+                    .setPackage(packageName);
+        }
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return mIntent != null ? AVAILABLE_UNSEARCHABLE : UNSUPPORTED_ON_DEVICE;
+    }
+
+    @Override
+    public boolean handlePreferenceTreeClick(Preference preference) {
+        if (TextUtils.equals(preference.getKey(), mPreferenceKey)) {
+            if (mIntent != null) {
+                mContext.startActivity(mIntent);
+            }
+            return true;
+        }
+        return false;
+    }
+}