Reply to accessibility method call even if semantics is not enabled (f…

…lutter#31063)

shell/platform/android/io/flutter/embedding/engine/systemchannels/AccessibilityChannel.java

@@ -2,6 +2,7 @@
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 import io.flutter.Log;
 import io.flutter.embedding.engine.FlutterJNI;
 import io.flutter.embedding.engine.dart.DartExecutor;
@@ -23,14 +24,16 @@ public class AccessibilityChannel {
   @NonNull public final FlutterJNI flutterJNI;
   @Nullable private AccessibilityMessageHandler handler;
 
-  private final BasicMessageChannel.MessageHandler<Object> parsingMessageHandler =
+  @VisibleForTesting
+  final BasicMessageChannel.MessageHandler<Object> parsingMessageHandler =
       new BasicMessageChannel.MessageHandler<Object>() {
         @Override
         public void onMessage(
             @Nullable Object message, @NonNull BasicMessageChannel.Reply<Object> reply) {
           // If there is no handler to respond to this message then we don't need to
           // parse it. Return.
           if (handler == null) {
+            reply.reply(null);
             return;
           }
 

shell/platform/android/test/io/flutter/FlutterTestSuite.java

@@ -26,6 +26,7 @@
 import io.flutter.embedding.engine.mutatorsstack.FlutterMutatorViewTest;
 import io.flutter.embedding.engine.plugins.shim.ShimPluginRegistryTest;
 import io.flutter.embedding.engine.renderer.FlutterRendererTest;
+import io.flutter.embedding.engine.systemchannels.AccessibilityChannelTest;
 import io.flutter.embedding.engine.systemchannels.DeferredComponentChannelTest;
 import io.flutter.embedding.engine.systemchannels.KeyEventChannelTest;
 import io.flutter.embedding.engine.systemchannels.PlatformChannelTest;
@@ -56,6 +57,7 @@
 @RunWith(Suite.class)
 @SuiteClasses({
   AccessibilityBridgeTest.class,
+  AccessibilityChannelTest.class,
   ApplicationInfoLoaderTest.class,
   BinaryCodecTest.class,
   DartExecutorTest.class,

shell/platform/android/test/io/flutter/embedding/engine/systemchannels/AccessibilityChannelTest.java

@@ -0,0 +1,33 @@
+package io.flutter.embedding.engine.systemchannels;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import android.annotation.TargetApi;
+import io.flutter.embedding.engine.FlutterJNI;
+import io.flutter.embedding.engine.dart.DartExecutor;
+import io.flutter.plugin.common.BasicMessageChannel;
+import org.json.JSONException;
+import org.json.JSONObject;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+@Config(
+    manifest = Config.NONE,
+    shadows = {})
+@RunWith(RobolectricTestRunner.class)
+@TargetApi(24)
+public class AccessibilityChannelTest {
+  @Test
+  public void repliesWhenNoAccessibilityHandler() throws JSONException {
+    AccessibilityChannel accessibilityChannel =
+        new AccessibilityChannel(mock(DartExecutor.class), mock(FlutterJNI.class));
+    JSONObject arguments = new JSONObject();
+    arguments.put("type", "announce");
+    BasicMessageChannel.Reply reply = mock(BasicMessageChannel.Reply.class);
+    accessibilityChannel.parsingMessageHandler.onMessage(arguments, reply);
+    verify(reply).reply(null);
+  }
+}