Disable screen saver setting for non-system users.

On devices where non-system users are not allowed to dream, disable the
screen saver setting when the current user is not the system user.

Bug: 213906883
Test: atest ScreenSaverPreferenceControllerTest
Test: Manually with the following steps:
Step 1: On a device with the config setting
config_dreamsOnlyEnabledForSystemUser set to false, make sure that
non-system users can still access the screen saver setting.
Step 2: On a device with the config setting
config_dreamsOnlyEnabledForSystemUser setting is set to true, make sure
that non-system users can not access (or see) the screen saver setting.
Step 3: Make sure that system users can still see the screen saver
setting on a device where config_dreamsOnlyEnabledForSystemUser is set
to true.

Change-Id: I7e167ed5a1ea183c725ba89a57b8d0b372064b82

src/com/android/settings/display/ScreenSaverPreferenceController.java

@@ -14,6 +14,7 @@
 package com.android.settings.display;
 
 import android.content.Context;
+import android.os.UserManager;
 
 import androidx.preference.Preference;
 
@@ -32,8 +33,11 @@ public class ScreenSaverPreferenceController extends AbstractPreferenceControlle
 
     @Override
     public boolean isAvailable() {
-        return mContext.getResources().getBoolean(
+        final boolean dreamsSupported = mContext.getResources().getBoolean(
                 com.android.internal.R.bool.config_dreamsSupported);
+        final boolean dreamsOnlyEnabledForSystemUser = mContext.getResources().getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser);
+        return dreamsSupported && (!dreamsOnlyEnabledForSystemUser || isSystemUser());
     }
 
     @Override
@@ -45,4 +49,9 @@ public class ScreenSaverPreferenceController extends AbstractPreferenceControlle
     public void updateState(Preference preference) {
         preference.setSummary(DreamSettings.getSummaryTextWithDreamName(mContext));
     }
+
+    private boolean isSystemUser() {
+        final UserManager userManager = mContext.getSystemService(UserManager.class);
+        return userManager.isSystemUser();
+    }
 }

tests/unit/src/com/android/settings/display/ScreenSaverPreferenceControllerTest.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2022 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.display;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.os.UserManager;
+
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.mockito.Spy;
+
+@RunWith(AndroidJUnit4.class)
+public class ScreenSaverPreferenceControllerTest {
+    @Spy
+    private final Context mContext = ApplicationProvider.getApplicationContext();
+    @Spy
+    private final Resources mResources = mContext.getResources();
+    @Mock
+    private UserManager mUserManager;
+
+    private ScreenSaverPreferenceController mController;
+
+    @Before
+    public void setup() {
+        MockitoAnnotations.initMocks(this);
+
+        mController = new ScreenSaverPreferenceController(mContext);
+
+        when(mContext.getResources()).thenReturn(mResources);
+        when(mContext.getSystemService(UserManager.class)).thenReturn(mUserManager);
+    }
+
+    @Test
+    public void isAvailable_dreamsEnabledForAllUsers_shouldBeTrueForSystemUser() {
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsSupported)).thenReturn(true);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser))
+                .thenReturn(false);
+        when(mUserManager.isSystemUser()).thenReturn(true);
+        assertTrue(mController.isAvailable());
+    }
+
+    @Test
+    public void isAvailable_dreamsEnabledForAllUsers_shouldBeTrueForNonSystemUser() {
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsSupported)).thenReturn(true);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser))
+                .thenReturn(false);
+        when(mUserManager.isSystemUser()).thenReturn(false);
+        assertTrue(mController.isAvailable());
+    }
+
+    @Test
+    public void isAvailable_dreamsDisabled_shouldBeFalseForSystemUser() {
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsSupported)).thenReturn(false);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser))
+                .thenReturn(false);
+        when(mUserManager.isSystemUser()).thenReturn(true);
+        assertFalse(mController.isAvailable());
+    }
+
+    @Test
+    public void isAvailable_dreamsOnlyEnabledForSystemUser_shouldBeTrueForSystemUser() {
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsSupported)).thenReturn(true);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser))
+                .thenReturn(true);
+        when(mUserManager.isSystemUser()).thenReturn(true);
+        assertTrue(mController.isAvailable());
+    }
+
+    @Test
+    public void isAvailable_dreamsOnlyEnabledForSystemUser_shouldBeFalseForNonSystemUser() {
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsSupported)).thenReturn(true);
+        when(mResources.getBoolean(
+                com.android.internal.R.bool.config_dreamsOnlyEnabledForSystemUser))
+                .thenReturn(true);
+        when(mUserManager.isSystemUser()).thenReturn(false);
+        assertFalse(mController.isAvailable());
+    }
+}