Add ability to show/hide System Update.

This adds one flag:
config_show_system_update_settings

Which when set to false will hide "System update" from System page. This
is useful for devices that controls its system update elsewhere.

Bug: 69813881
Test: make RunSettingsRoboTests
ROBOTEST_FILTER=com.android.settings.deviceinfo
Change-Id: Ibd1291ffd8948419e8aa06d0721842246a069378

res/values/bools.xml

@@ -155,4 +155,7 @@
 
     <!-- Whether assist_and_voice_input should be shown or not. -->
     <bool name="config_show_assist_and_voice_input">true</bool>
+
+    <!-- Whether system_update_settings should be shown or not. -->
+    <bool name="config_show_system_update_settings">true</bool>
 </resources>

src/com/android/settings/deviceinfo/SystemUpdatePreferenceController.java

@@ -47,7 +47,8 @@ public class SystemUpdatePreferenceController extends BasePreferenceController {
 
     @Override
     public int getAvailabilityStatus() {
-        return mUm.isAdminUser()
+        return mContext.getResources().getBoolean(R.bool.config_show_system_update_settings)
+                && mUm.isAdminUser()
                 ? AVAILABLE
                 : DISABLED_UNSUPPORTED;
     }

tests/robotests/res/values-mcc999/config.xml

@@ -55,5 +55,6 @@
     <bool name="config_show_vibrate_input_devices">false</bool>
     <bool name="config_show_color_correction_preference">false</bool>
     <bool name="config_show_color_inversion_preference">false</bool>
+    <bool name="config_show_system_update_settings">false</bool>
     <bool name="config_wifi_support_connected_mac_randomization">false</bool>
 </resources>

tests/robotests/src/com/android/settings/deviceinfo/SystemUpdatePreferenceControllerTest.java

@@ -16,7 +16,9 @@
 package com.android.settings.deviceinfo;
 
 import static com.google.common.truth.Truth.assertThat;
+
 import static org.mockito.Answers.RETURNS_DEEP_STUBS;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
 
 import android.content.Context;
@@ -28,6 +30,7 @@ import android.support.v7.preference.PreferenceScreen;
 import com.android.settings.R;
 import com.android.settings.TestConfig;
 import com.android.settings.testutils.SettingsRobolectricTestRunner;
+import com.android.settings.testutils.shadow.ShadowUserManager;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -36,29 +39,32 @@ import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.RuntimeEnvironment;
 import org.robolectric.annotation.Config;
+import org.robolectric.shadows.ShadowApplication;
 
 import java.util.ArrayList;
 import java.util.List;
 
 @RunWith(SettingsRobolectricTestRunner.class)
-@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+@Config(
+        manifest = TestConfig.MANIFEST_PATH,
+        sdk = TestConfig.SDK_VERSION,
+        shadows = {
+                ShadowUserManager.class
+        })
 public class SystemUpdatePreferenceControllerTest {
 
-    @Mock(answer = RETURNS_DEEP_STUBS)
-    private Context mContext;
-    @Mock
-    private UserManager mUserManager;
     @Mock
     private PreferenceScreen mScreen;
 
+    private Context mContext;
     private SystemUpdatePreferenceController mController;
     private Preference mPreference;
 
     @Before
     public void setUp() {
         MockitoAnnotations.initMocks(this);
+        mContext = RuntimeEnvironment.application;
 
-        when(mContext.getSystemService(Context.USER_SERVICE)).thenReturn(mUserManager);
         mController = new SystemUpdatePreferenceController(mContext);
         mPreference = new Preference(RuntimeEnvironment.application);
         mPreference.setKey(mController.getPreferenceKey());
@@ -68,7 +74,7 @@ public class SystemUpdatePreferenceControllerTest {
     @Test
     public void updateNonIndexable_ifAvailable_shouldNotUpdate() {
         final List<String> keys = new ArrayList<>();
-        when(mUserManager.isAdminUser()).thenReturn(true);
+        ShadowUserManager.getShadow().setIsAdminUser(true);
 
         mController.updateNonIndexableKeys(keys);
 
@@ -77,7 +83,7 @@ public class SystemUpdatePreferenceControllerTest {
 
     @Test
     public void updateNonIndexable_ifNotAvailable_shouldUpdate() {
-        // mUserManager.isAdminUser() returns false here
+        ShadowUserManager.getShadow().setIsAdminUser(false);
         final List<String> keys = new ArrayList<>();
 
         mController.updateNonIndexableKeys(keys);
@@ -86,8 +92,17 @@ public class SystemUpdatePreferenceControllerTest {
     }
 
     @Test
-    public void displayPrefs_ifNotAvailable_shouldNotDisplay() {
-        // mUserManager.isAdminUser() returns false here
+    public void displayPrefs_ifVisible_butNotAdminUser_shouldNotDisplay() {
+        ShadowUserManager.getShadow().setIsAdminUser(false);
+        mController.displayPreference(mScreen);
+
+        assertThat(mPreference.isVisible()).isFalse();
+    }
+
+    @Test
+    @Config(qualifiers = "mcc999")
+    public void displayPrefs_ifAdminUser_butNotVisible_shouldNotDisplay() {
+        ShadowUserManager.getShadow().setIsAdminUser(true);
         mController.displayPreference(mScreen);
 
         assertThat(mPreference.isVisible()).isFalse();
@@ -95,7 +110,7 @@ public class SystemUpdatePreferenceControllerTest {
 
     @Test
     public void displayPrefs_ifAvailable_shouldDisplay() {
-        when(mUserManager.isAdminUser()).thenReturn(true);
+        ShadowUserManager.getShadow().setIsAdminUser(true);
 
         mController.displayPreference(mScreen);
 
@@ -104,8 +119,6 @@ public class SystemUpdatePreferenceControllerTest {
 
     @Test
     public void updateState_shouldSetToAndroidVersion() {
-        mController = new SystemUpdatePreferenceController(RuntimeEnvironment.application);
-
         mController.updateState(mPreference);
 
         assertThat(mPreference.getSummary())