Add a feature flag for AdServices System Service receiver registration

- Add Flags and PhFlags that uses DeviceConfig
- Define a flag to enable the AdServiceSystemServiceBroadcastReceiver
- This will make sure that when the flag is disabled, we will not
register any Receiver.

Bug: 247581193
Test: presubmit
Change-Id: I24582e19909241001f1665c73eab36b31e89fea4

7 files changed, 360 insertions, 48 deletions

diff --git a/adservices/service/java/com/android/server/adservices/AdServicesManagerService.java b/adservices/service/java/com/android/server/adservices/AdServicesManagerService.java
index 1f87123c9e..ccffefa5ea 100644
--- a/adservices/service/java/com/android/server/adservices/AdServicesManagerService.java
+++ b/adservices/service/java/com/android/server/adservices/AdServicesManagerService.java
@@ -24,6 +24,7 @@ import android.content.pm.ResolveInfo;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.UserHandle;
+import android.provider.DeviceConfig;
 import android.util.Log;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -57,20 +58,30 @@ public class AdServicesManagerService {
     private static final String PACKAGE_DATA_CLEARED = "package_data_cleared";
 
     private final Context mContext;
-    private final Handler mHandler;
+
+    BroadcastReceiver mSystemServicePackageChangedReceiver;
+
+    // This will be triggered when there is a flag change.
+    private final DeviceConfig.OnPropertiesChangedListener mOnFlagsChangedListener =
+            properties -> {
+                if (!properties.getNamespace().equals(DeviceConfig.NAMESPACE_ADSERVICES)) {
+                    return;
+                }
+                registerPackagedChangedBroadcastReceivers();
+            };
 
     @VisibleForTesting
     AdServicesManagerService(Context context) {
         mContext = context;
 
-        // Start the handler thread.
-        HandlerThread handlerThread = new HandlerThread("AdServicesManagerServiceHandler");
-        handlerThread.start();
-        mHandler = new Handler(handlerThread.getLooper());
+        DeviceConfig.addOnPropertiesChangedListener(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                mContext.getMainExecutor(),
+                mOnFlagsChangedListener);
+
         registerPackagedChangedBroadcastReceivers();
     }
 
-
     /** @hide */
     public static class Lifecycle extends SystemService {
         private AdServicesManagerService mService;
@@ -93,28 +104,60 @@ public class AdServicesManagerService {
      * the device at boot up. After receiving the broadcast, send an explicit broadcast to the
      * AdServices module as that user.
      */
-    private void registerPackagedChangedBroadcastReceivers() {
-        final IntentFilter packageChangedIntentFilter = new IntentFilter();
-
-        packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_FULLY_REMOVED);
-        packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_DATA_CLEARED);
-        packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
-        packageChangedIntentFilter.addDataScheme("package");
-
-        BroadcastReceiver systemServicePackageChangedReceiver =
-                new BroadcastReceiver() {
-                    @Override
-                    public void onReceive(Context context, Intent intent) {
-                        UserHandle user = getSendingUser();
-                        mHandler.post(() -> onPackageChange(intent, user));
-                    }
-                };
-        mContext.registerReceiverForAllUsers(
-                systemServicePackageChangedReceiver,
-                packageChangedIntentFilter,
-                /* broadcastPermission */ null,
-                mHandler);
-        Log.d(TAG, "Package changed broadcast receivers registered.");
+    @VisibleForTesting
+    void registerPackagedChangedBroadcastReceivers() {
+        // There could be race condition between registerPackagedChangedBroadcastReceivers call
+        // in the AdServicesManagerService constructor and the mOnFlagsChangedListener.
+        synchronized (AdServicesManagerService.class) {
+            if (FlagsFactory.getFlags().getAdServicesSystemServiceEnabled()) {
+                if (mSystemServicePackageChangedReceiver != null) {
+                    // We already register the receiver.
+                    Log.d(TAG, "SystemServicePackageChangedReceiver is already registered.");
+                    return;
+                }
+
+                // mSystemServicePackageChangedReceiver == null
+                // We haven't registered the receiver.
+                // Start the handler thread.
+                HandlerThread handlerThread = new HandlerThread("AdServicesManagerServiceHandler");
+                handlerThread.start();
+                Handler handler = new Handler(handlerThread.getLooper());
+
+                final IntentFilter packageChangedIntentFilter = new IntentFilter();
+
+                packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_FULLY_REMOVED);
+                packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_DATA_CLEARED);
+                packageChangedIntentFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
+                packageChangedIntentFilter.addDataScheme("package");
+
+                mSystemServicePackageChangedReceiver =
+                        new BroadcastReceiver() {
+                            @Override
+                            public void onReceive(Context context, Intent intent) {
+                                UserHandle user = getSendingUser();
+                                handler.post(() -> onPackageChange(intent, user));
+                            }
+                        };
+                mContext.registerReceiverForAllUsers(
+                        mSystemServicePackageChangedReceiver,
+                        packageChangedIntentFilter,
+                        /* broadcastPermission */ null,
+                        handler);
+                Log.d(TAG, "Package changed broadcast receivers registered.");
+            } else {
+                // FlagsFactory.getFlags().getAdServicesSystemServiceEnabled() == false
+                Log.d(TAG, "AdServicesSystemServiceEnabled is FALSE.");
+
+                // If there is a SystemServicePackageChangeReceiver, unregister it.
+                if (mSystemServicePackageChangedReceiver != null) {
+                    Log.d(TAG, "Unregistering the existing SystemServicePackageChangeReceiver");
+                    mContext.unregisterReceiver(mSystemServicePackageChangedReceiver);
+                    mSystemServicePackageChangedReceiver = null;
+                }
+
+                return;
+            }
+        }
     }
 
     /** Sends an explicit broadcast to the AdServices module when a package change occurs. */
diff --git a/adservices/service/java/com/android/server/adservices/Flags.java b/adservices/service/java/com/android/server/adservices/Flags.java
new file mode 100644
index 0000000000..925f88db29
--- /dev/null
+++ b/adservices/service/java/com/android/server/adservices/Flags.java
@@ -0,0 +1,35 @@
+/*
+ * 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.server.adservices;
+
+/**
+ * AdServices System Service Feature Flags interface. This Flags interface hold the default values
+ * of AdServices System Service Flags.
+ *
+ * @hide
+ */
+interface Flags {
+    /**
+     * Whether to enable the AdServices System Service. By default, the AdServices System Service is
+     * disabled.
+     */
+    boolean ADSERVICES_SYSTEM_SERVICE_ENABLED = false;
+
+    default boolean getAdServicesSystemServiceEnabled() {
+        return ADSERVICES_SYSTEM_SERVICE_ENABLED;
+    }
+}
diff --git a/adservices/service/java/com/android/server/adservices/FlagsFactory.java b/adservices/service/java/com/android/server/adservices/FlagsFactory.java
new file mode 100644
index 0000000000..e6c4030aed
--- /dev/null
+++ b/adservices/service/java/com/android/server/adservices/FlagsFactory.java
@@ -0,0 +1,30 @@
+/*
+ * 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.server.adservices;
+
+/**
+ * Factory class to create AdServices System Service Flags
+ *
+ * @hide
+ */
+public class FlagsFactory {
+    /** AdServices System Service Flags backed by PH. */
+    public static Flags getFlags() {
+        // Use the Flags backed by PH.
+        return PhFlags.getInstance();
+    }
+}
diff --git a/adservices/service/java/com/android/server/adservices/PhFlags.java b/adservices/service/java/com/android/server/adservices/PhFlags.java
new file mode 100644
index 0000000000..89ed912ed0
--- /dev/null
+++ b/adservices/service/java/com/android/server/adservices/PhFlags.java
@@ -0,0 +1,50 @@
+/*
+ * 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.server.adservices;
+
+import android.annotation.NonNull;
+import android.provider.DeviceConfig;
+
+/**
+ * Flags Implementation that delegates to DeviceConfig.
+ *
+ * @hide
+ */
+public final class PhFlags implements Flags {
+
+    private static final PhFlags sSingleton = new PhFlags();
+
+    /** Returns the singleton instance of the PhFlags. */
+    @NonNull
+    public static PhFlags getInstance() {
+        return sSingleton;
+    }
+
+    /*
+     * Keys for ALL the flags stored in DeviceConfig.
+     */
+    // Adservices System Service enable status keys.
+    static final String KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED = "adservice_system_service_enabled";
+
+    @Override
+    public boolean getAdServicesSystemServiceEnabled() {
+        // The priority of applying the flag values: PH (DeviceConfig) and then hard-coded value.
+        return DeviceConfig.getBoolean(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                /* flagName */ KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED,
+                /* defaultValue */ ADSERVICES_SYSTEM_SERVICE_ENABLED);
+    }
+}
diff --git a/adservices/tests/unittest/system-service/Android.bp b/adservices/tests/unittest/system-service/Android.bp
index 8d69bff677..a3757ad410 100644
--- a/adservices/tests/unittest/system-service/Android.bp
+++ b/adservices/tests/unittest/system-service/Android.bp
@@ -22,6 +22,7 @@ android_test {
         "src/com/android/server/adservices/*.java",
         "src/**/*.java",
     ],
+    defaults: ["modules-utils-testable-device-config-defaults"],
     manifest: "AndroidManifest.xml",
     test_config: "AndroidTest.xml",
     static_libs: [
diff --git a/adservices/tests/unittest/system-service/src/com/android/server/adservices/AdServicesManagerServiceTest.java b/adservices/tests/unittest/system-service/src/com/android/server/adservices/AdServicesManagerServiceTest.java
index aab7236ed4..9e168b124c 100644
--- a/adservices/tests/unittest/system-service/src/com/android/server/adservices/AdServicesManagerServiceTest.java
+++ b/adservices/tests/unittest/system-service/src/com/android/server/adservices/AdServicesManagerServiceTest.java
@@ -16,23 +16,39 @@
 
 package com.android.server.adservices;
 
+import static com.android.server.adservices.PhFlags.KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+
 import android.Manifest;
+import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.content.IntentFilter;
 import android.net.Uri;
+import android.os.Handler;
 import android.os.UserHandle;
+import android.provider.DeviceConfig;
 
 import androidx.test.platform.app.InstrumentationRegistry;
 
-import com.google.common.truth.Truth;
+import com.android.modules.utils.testing.TestableDeviceConfig;
 
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
 
 /** Tests for {@link AdServicesManagerService} */
 public class AdServicesManagerServiceTest {
+    @Rule
+    public final TestableDeviceConfig.TestableDeviceConfigRule mDeviceConfigRule =
+            new TestableDeviceConfig.TestableDeviceConfigRule();
+
     private AdServicesManagerService mService;
     private Context mSpyContext;
     private static final String PACKAGE_NAME = "com.package.example";
@@ -45,18 +61,100 @@ public class AdServicesManagerServiceTest {
 
     @Before
     public void setup() {
+        MockitoAnnotations.initMocks(this);
+
         Context context = InstrumentationRegistry.getInstrumentation().getContext();
         mSpyContext = Mockito.spy(context);
 
         InstrumentationRegistry.getInstrumentation()
                 .getUiAutomation()
                 .adoptShellPermissionIdentity(Manifest.permission.INTERACT_ACROSS_USERS_FULL);
+    }
 
+    @Test
+    public void testAdServicesSystemService_enabled_then_disabled() {
+        // First enable the flag.
+        DeviceConfig.setProperty(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED,
+                Boolean.toString(Boolean.TRUE),
+                /* makeDefault */ false);
+
+        // This will trigger the registration of the Receiver.
         mService = new AdServicesManagerService(mSpyContext);
+
+        ArgumentCaptor<BroadcastReceiver> argumentReceiver =
+                ArgumentCaptor.forClass(BroadcastReceiver.class);
+        ArgumentCaptor<IntentFilter> argumentIntentFilter =
+                ArgumentCaptor.forClass(IntentFilter.class);
+        ArgumentCaptor<String> argumentPermission = ArgumentCaptor.forClass(String.class);
+        ArgumentCaptor<Handler> argumentHandler = ArgumentCaptor.forClass(Handler.class);
+
+        // Calling the second time will not register again.
+        mService.registerPackagedChangedBroadcastReceivers();
+
+        // The flag is enabled so we call registerReceiverForAllUsers
+        Mockito.verify(mSpyContext, Mockito.times(1))
+                .registerReceiverForAllUsers(
+                        argumentReceiver.capture(),
+                        argumentIntentFilter.capture(),
+                        argumentPermission.capture(),
+                        argumentHandler.capture());
+
+        BroadcastReceiver receiver = argumentReceiver.getValue();
+        assertThat(receiver).isNotNull();
+
+        assertThat(argumentIntentFilter.getValue().getAction(0))
+                .isEqualTo(Intent.ACTION_PACKAGE_FULLY_REMOVED);
+        assertThat(argumentIntentFilter.getValue().getAction(1))
+                .isEqualTo(Intent.ACTION_PACKAGE_DATA_CLEARED);
+        assertThat(argumentIntentFilter.getValue().getAction(2))
+                .isEqualTo(Intent.ACTION_PACKAGE_ADDED);
+        assertThat(argumentIntentFilter.getValue().getDataScheme(0)).isEqualTo("package");
+
+        assertThat(argumentPermission.getValue()).isNull();
+        assertThat(argumentHandler.getValue()).isNotNull();
+
+        // Now disable the flag.
+        DeviceConfig.setProperty(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED,
+                Boolean.toString(Boolean.FALSE),
+                /* makeDefault */ false);
+
+        // Calling when the flag is disabled will unregister the Receiver!
+        mService.registerPackagedChangedBroadcastReceivers();
+        Mockito.verify(mSpyContext, Mockito.times(1))
+                .unregisterReceiver(argumentReceiver.capture());
+
+        // The unregistered is called on the same receiver when registered above.
+        assertThat(argumentReceiver.getValue()).isSameInstanceAs(receiver);
+    }
+
+    @Test
+    public void testAdServicesSystemService_disabled() {
+        // Disable the flag.
+        DeviceConfig.setProperty(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED,
+                Boolean.toString(Boolean.FALSE),
+                /* makeDefault */ false);
+
+        mService = new AdServicesManagerService(mSpyContext);
+
+        // The flag is disabled so there is no registerReceiverForAllUsers
+        Mockito.verify(mSpyContext, Mockito.times(0))
+                .registerReceiverForAllUsers(
+                        any(BroadcastReceiver.class),
+                        any(IntentFilter.class),
+                        any(String.class),
+                        any(Handler.class));
     }
 
     @Test
     public void testSendBroadcastForPackageFullyRemoved() {
+        mService = new AdServicesManagerService(mSpyContext);
+
         Intent i = new Intent(Intent.ACTION_PACKAGE_FULLY_REMOVED);
         i.setData(Uri.parse("package:" + PACKAGE_NAME));
         i.putExtra(Intent.EXTRA_UID, PACKAGE_UID);
@@ -70,18 +168,19 @@ public class AdServicesManagerServiceTest {
         Mockito.verify(mSpyContext, Mockito.times(1))
                 .sendBroadcastAsUser(argumentIntent.capture(), argumentUser.capture());
 
-        Truth.assertThat(argumentIntent.getValue().getAction())
-                .isEqualTo(PACKAGE_CHANGED_BROADCAST);
-        Truth.assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
-        Truth.assertThat(argumentIntent.getValue().getStringExtra("action"))
+        assertThat(argumentIntent.getValue().getAction()).isEqualTo(PACKAGE_CHANGED_BROADCAST);
+        assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
+        assertThat(argumentIntent.getValue().getStringExtra("action"))
                 .isEqualTo(PACKAGE_FULLY_REMOVED);
-        Truth.assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
+        assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
                 .isEqualTo(PACKAGE_UID);
-        Truth.assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
+        assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
     }
 
     @Test
     public void testSendBroadcastForPackageAdded() {
+        mService = new AdServicesManagerService(mSpyContext);
+
         Intent i = new Intent(Intent.ACTION_PACKAGE_ADDED);
         i.setData(Uri.parse("package:" + PACKAGE_NAME));
         i.putExtra(Intent.EXTRA_UID, PACKAGE_UID);
@@ -96,18 +195,18 @@ public class AdServicesManagerServiceTest {
         Mockito.verify(mSpyContext, Mockito.times(1))
                 .sendBroadcastAsUser(argumentIntent.capture(), argumentUser.capture());
 
-        Truth.assertThat(argumentIntent.getValue().getAction())
-                .isEqualTo(PACKAGE_CHANGED_BROADCAST);
-        Truth.assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
-        Truth.assertThat(argumentIntent.getValue().getStringExtra("action"))
-                .isEqualTo(PACKAGE_ADDED);
-        Truth.assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
+        assertThat(argumentIntent.getValue().getAction()).isEqualTo(PACKAGE_CHANGED_BROADCAST);
+        assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
+        assertThat(argumentIntent.getValue().getStringExtra("action")).isEqualTo(PACKAGE_ADDED);
+        assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
                 .isEqualTo(PACKAGE_UID);
-        Truth.assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
+        assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
     }
 
     @Test
     public void testSendBroadcastForPackageDataCleared() {
+        mService = new AdServicesManagerService(mSpyContext);
+
         Intent i = new Intent(Intent.ACTION_PACKAGE_DATA_CLEARED);
         i.setData(Uri.parse("package:" + PACKAGE_NAME));
         i.putExtra(Intent.EXTRA_UID, PACKAGE_UID);
@@ -121,13 +220,12 @@ public class AdServicesManagerServiceTest {
         Mockito.verify(mSpyContext, Mockito.times(1))
                 .sendBroadcastAsUser(argumentIntent.capture(), argumentUser.capture());
 
-        Truth.assertThat(argumentIntent.getValue().getAction())
-                .isEqualTo(PACKAGE_CHANGED_BROADCAST);
-        Truth.assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
-        Truth.assertThat(argumentIntent.getValue().getStringExtra("action"))
+        assertThat(argumentIntent.getValue().getAction()).isEqualTo(PACKAGE_CHANGED_BROADCAST);
+        assertThat(argumentIntent.getValue().getData()).isEqualTo(i.getData());
+        assertThat(argumentIntent.getValue().getStringExtra("action"))
                 .isEqualTo(PACKAGE_DATA_CLEARED);
-        Truth.assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
+        assertThat(argumentIntent.getValue().getIntExtra(Intent.EXTRA_UID, -1))
                 .isEqualTo(PACKAGE_UID);
-        Truth.assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
+        assertThat(argumentUser.getValue()).isEqualTo(mSpyContext.getUser());
     }
 }
diff --git a/adservices/tests/unittest/system-service/src/com/android/server/adservices/PhFlagsTest.java b/adservices/tests/unittest/system-service/src/com/android/server/adservices/PhFlagsTest.java
new file mode 100644
index 0000000000..dfd8b80b0a
--- /dev/null
+++ b/adservices/tests/unittest/system-service/src/com/android/server/adservices/PhFlagsTest.java
@@ -0,0 +1,55 @@
+/*
+ * 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.server.adservices;
+
+import static com.android.server.adservices.Flags.ADSERVICES_SYSTEM_SERVICE_ENABLED;
+import static com.android.server.adservices.PhFlags.KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED;
+
+import android.provider.DeviceConfig;
+
+import com.android.modules.utils.testing.TestableDeviceConfig;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import org.junit.Rule;
+import org.junit.Test;
+
+public class PhFlagsTest {
+
+    @Rule
+    public final TestableDeviceConfig.TestableDeviceConfigRule mDeviceConfigRule =
+            new TestableDeviceConfig.TestableDeviceConfigRule();
+
+    @Test
+    public void testAdServicesSystemServiceEnabled() {
+        // Without any overriding, the value is the hard coded constant.
+        assertThat(FlagsFactory.getFlags().getAdServicesSystemServiceEnabled())
+                .isEqualTo(ADSERVICES_SYSTEM_SERVICE_ENABLED);
+
+        // Now overriding with the value from PH.
+        final boolean phOverridingValue = true;
+
+        DeviceConfig.setProperty(
+                DeviceConfig.NAMESPACE_ADSERVICES,
+                KEY_ADSERVICES_SYSTEM_SERVICE_ENABLED,
+                Boolean.toString(phOverridingValue),
+                /* makeDefault */ false);
+
+        Flags phFlags = FlagsFactory.getFlags();
+        assertThat(phFlags.getAdServicesSystemServiceEnabled()).isEqualTo(phOverridingValue);
+    }
+}