Add accessibility usage preference to the Privacy screen.

Bug: 123595964
Test: Open Privacy page with one and two accessibility services
enabled and click the preference.
Test: Open Privacy page with zero accessibility services enabled and
do not see the preference.
Test: atest AccessibilityUsagePreferenceControllerTest

Change-Id: Ib1dab374cb53dfbc473b2d5ac49115e608a13ab8

res/values/strings.xml

@@ -10624,6 +10624,15 @@
     <!-- Text for permission bar chart details in Privacy page.  [CHAR LIMIT=NONE] -->
     <string name="permission_bar_chart_details">See all usage</string>
 
+    <!-- Title for the accessibility usage preference in the Privacy page.  [CHAR LIMIT=NONE] -->
+    <string name="accessibility_usage_title">Accessibility usage</string>
+
+    <!-- Summary for the accessibility usage preference in the Privacy page.  [CHAR LIMIT=NONE] -->
+    <plurals name="accessibility_usage_summary">
+        <item quantity="one">1 service has full access to your device</item>
+        <item quantity="other"><xliff:g id="service_count">%1$d</xliff:g> services have full access to your device</item>
+    </plurals>
+
     <!-- Title for notification channel slice. [CHAR LIMIT=NONE] -->
     <string name="manage_app_notification">Manage <xliff:g id="app_name" example="Settings">%1$s</xliff:g> Notifications</string>
     <!-- Title for no suggested app in notification channel slice. [CHAR LIMIT=NONE] -->

res/xml/privacy_dashboard_settings.xml

@@ -20,13 +20,22 @@
     xmlns:settings="http://schemas.android.com/apk/res-auto"
     android:key="privacy_dashboard_page"
     android:title="@string/privacy_dashboard_title"
-    settings:initialExpandedChildrenCount="3">
+    settings:initialExpandedChildrenCount="4">
 
     <com.android.settingslib.widget.BarChartPreference
         android:key="permission_bar_chart"
         android:title="@string/privacy_dashboard_title"
         settings:controller="com.android.settings.privacy.PermissionBarChartPreferenceController"/>
 
+    <!-- Accessibility usage -->
+    <Preference
+        android:key="privacy_accessibility_usage"
+        android:title="@string/accessibility_usage_title"
+        settings:allowDividerAbove="true"
+        settings:controller="com.android.settings.privacy.AccessibilityUsagePreferenceController">
+        <intent android:action="android.intent.action.REVIEW_ACCESSIBILITY_SERVICES"/>
+    </Preference>
+
     <!-- App permissions -->
     <Preference
         android:key="privacy_manage_perms"

src/com/android/settings/privacy/AccessibilityUsagePreferenceController.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 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.privacy;
+
+import android.accessibilityservice.AccessibilityServiceInfo;
+import android.content.Context;
+import android.view.accessibility.AccessibilityManager;
+
+import androidx.annotation.NonNull;
+import androidx.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settings.core.BasePreferenceController;
+
+import java.util.List;
+
+
+public class AccessibilityUsagePreferenceController extends BasePreferenceController  {
+
+    private final @NonNull List<AccessibilityServiceInfo> mEnabledServiceInfos;
+
+    public AccessibilityUsagePreferenceController(Context context, String preferenceKey) {
+        super(context, preferenceKey);
+
+        final AccessibilityManager accessibilityManager = context.getSystemService(
+                AccessibilityManager.class);
+        mEnabledServiceInfos = accessibilityManager.getEnabledAccessibilityServiceList(
+                AccessibilityServiceInfo.FEEDBACK_ALL_MASK);
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return mEnabledServiceInfos.isEmpty() ? UNSUPPORTED_ON_DEVICE : AVAILABLE;
+    }
+
+    @Override
+    public CharSequence getSummary() {
+        return mContext.getResources().getQuantityString(R.plurals.accessibility_usage_summary,
+                mEnabledServiceInfos.size(), mEnabledServiceInfos.size());
+    }
+}

tests/robotests/src/com/android/settings/privacy/AccessibilityUsagePreferenceControllerTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2019 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.privacy;
+
+import static com.android.settings.core.BasePreferenceController.AVAILABLE;
+import static com.android.settings.core.BasePreferenceController.UNSUPPORTED_ON_DEVICE;
+
+import static com.google.common.truth.Truth.assertThat;
+import android.accessibilityservice.AccessibilityServiceInfo;
+import android.content.Context;
+import android.view.accessibility.AccessibilityManager;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.shadow.api.Shadow;
+import org.robolectric.shadows.ShadowAccessibilityManager;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+@RunWith(RobolectricTestRunner.class)
+public class AccessibilityUsagePreferenceControllerTest {
+
+    private Context mContext;
+    private ShadowAccessibilityManager mAccessibilityManager;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mContext = RuntimeEnvironment.application;
+        mAccessibilityManager = Shadow.extract(
+                RuntimeEnvironment.application.getSystemService(AccessibilityManager.class));
+    }
+
+    @After
+    public void tearDown() {
+        ShadowAccessibilityManager.reset();
+    }
+
+    @Test
+    public void getAvailabilityStatus_noEnabledServices_shouldReturnUnsupported() {
+        mAccessibilityManager.setEnabledAccessibilityServiceList(new ArrayList<>());
+        AccessibilityUsagePreferenceController controller =
+                new AccessibilityUsagePreferenceController(mContext, "test_key");
+
+        assertThat(controller.getAvailabilityStatus()).isEqualTo(UNSUPPORTED_ON_DEVICE);
+    }
+
+    @Test
+    public void getAvailabilityStatus_enabledServices_shouldReturnAvailableUnsearchable() {
+        mAccessibilityManager.setEnabledAccessibilityServiceList(
+                new ArrayList<>(Arrays.asList(new AccessibilityServiceInfo())));
+        AccessibilityUsagePreferenceController controller =
+                new AccessibilityUsagePreferenceController(mContext, "test_key");
+
+        assertThat(controller.getAvailabilityStatus()).isEqualTo(AVAILABLE);
+    }
+}