Expose lockdown button in settings

Test: manually verified toggle controls lockdown button visibility
Test: make RunSettingsRoboTests
Bug: 37221346
Change-Id: Ie59f9c6a1df1d877b18986c6a58492a5aa789d34

src/com/android/settings/security/LockdownButtonPreferenceController.java

@@ -0,0 +1,61 @@
+/*
+ * 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.security;
+
+import android.content.Context;
+import android.os.UserHandle;
+import android.provider.Settings;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.TwoStatePreference;
+
+import com.android.internal.widget.LockPatternUtils;
+import com.android.settings.core.BasePreferenceController;
+import com.android.settings.core.TogglePreferenceController;
+
+public class LockdownButtonPreferenceController extends TogglePreferenceController {
+
+    private static final String KEY_LOCKDOWN_ENALBED = "security_setting_lockdown_enabled";
+
+    private final LockPatternUtils mLockPatternUtils;
+
+    public LockdownButtonPreferenceController(Context context) {
+        super(context, KEY_LOCKDOWN_ENALBED);
+        mLockPatternUtils = new LockPatternUtils(context);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        if (mLockPatternUtils.isSecure(UserHandle.myUserId())) {
+            return BasePreferenceController.AVAILABLE;
+        } else {
+            return BasePreferenceController.DISABLED_FOR_USER;
+        }
+    }
+
+    @Override
+    public boolean isChecked() {
+        return Settings.Secure.getInt(mContext.getContentResolver(),
+                Settings.Secure.LOCKDOWN_IN_POWER_MENU, 0) != 0;
+    }
+
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        Settings.Secure.putInt(mContext.getContentResolver(),
+                Settings.Secure.LOCKDOWN_IN_POWER_MENU, isChecked ? 1 : 0);
+        return true;
+    }
+}

src/com/android/settings/security/LockscreenDashboardFragment.java

@@ -93,6 +93,8 @@ public class LockscreenDashboardFragment extends DashboardFragment
         mOwnerInfoPreferenceController =
                 new OwnerInfoPreferenceController(context, this, lifecycle);
         controllers.add(mOwnerInfoPreferenceController);
+        controllers.add(new LockdownButtonPreferenceController(context));
+
         return controllers;
     }
 
@@ -122,6 +124,7 @@ public class LockscreenDashboardFragment extends DashboardFragment
                             KEY_ADD_USER_FROM_LOCK_SCREEN));
                     controllers.add(new OwnerInfoPreferenceController(
                             context, null /* fragment */, null /* lifecycle */));
+                    controllers.add(new LockdownButtonPreferenceController(context));
                     return controllers;
                 }