Allow onGetSliceDescendants to be slow

Because sometimes it needs to be

Test: existing tests
Bug: 79132845
Bug: 77873463
Change-Id: I93aa8553c48c856bf96c347a229be6e770751708

core/java/android/app/slice/SliceManager.java

@@ -23,6 +23,7 @@ import android.annotation.Nullable;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.annotation.SystemService;
+import android.annotation.WorkerThread;
 import android.content.ContentProviderClient;
 import android.content.ContentResolver;
 import android.content.Context;
@@ -217,6 +218,7 @@ public class SliceManager {
      * @return All slices within the space.
      * @see SliceProvider#onGetSliceDescendants(Uri)
      */
+    @WorkerThread
     public @NonNull Collection<Uri> getSliceDescendants(@NonNull Uri uri) {
         ContentResolver resolver = mContext.getContentResolver();
         try (ContentProviderClient provider = resolver.acquireContentProviderClient(uri)) {

core/java/android/app/slice/SliceProvider.java

@@ -398,12 +398,7 @@ public abstract class SliceProvider extends ContentProvider {
 
     private Collection<Uri> handleGetDescendants(Uri uri) {
         mCallback = "onGetSliceDescendants";
-        Handler.getMain().postDelayed(mAnr, SLICE_BIND_ANR);
-        try {
-            return onGetSliceDescendants(uri);
-        } finally {
-            Handler.getMain().removeCallbacks(mAnr);
-        }
+        return onGetSliceDescendants(uri);
     }
 
     private void handlePinSlice(Uri sliceUri) {