Delegate PrintServicesLoader to the framework's one

1. Remove the duplicated PrintServicesLoader in Settings
2. Make a androidx.loader in Settings and internally just delegate all calls to the real PrintServicesLoader
3. Get the result from the real loader

Test: manual
Fixes: 111581651
Change-Id: I2a9b3653f5c68f8383a468cd16ef5f7c3fd4bc3a

src/com/android/settings/print/SettingsPrintServicesLoader.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2018 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.print;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.print.PrintManager;
+import android.print.PrintServicesLoader;
+import android.printservice.PrintServiceInfo;
+
+import com.android.internal.util.Preconditions;
+
+import java.util.List;
+
+import androidx.loader.content.Loader;
+
+/**
+ * Loader for the list of print services. Can be parametrized to select a subset.
+ */
+public class SettingsPrintServicesLoader extends Loader<List<PrintServiceInfo>> {
+
+    private PrintServicesLoader mLoader;
+
+    public SettingsPrintServicesLoader(@NonNull PrintManager printManager, @NonNull Context context,
+            int selectionFlags) {
+        super(Preconditions.checkNotNull(context));
+
+        mLoader = new PrintServicesLoader(printManager, context, selectionFlags) {
+            @Override
+            public void deliverResult(List<PrintServiceInfo> data) {
+                super.deliverResult(data);
+
+                // deliver the result to outer Loader class
+                SettingsPrintServicesLoader.this.deliverResult(data);
+            }
+        };
+    }
+
+    @Override
+    protected void onForceLoad() {
+        mLoader.forceLoad();
+    }
+
+    @Override
+    protected void onStartLoading() {
+        mLoader.startLoading();
+    }
+
+    @Override
+    protected void onStopLoading() {
+        mLoader.stopLoading();
+    }
+
+    @Override
+    protected boolean onCancelLoad() {
+        return mLoader.cancelLoad();
+    }
+
+    @Override
+    protected void onAbandon() {
+        mLoader.abandon();
+    }
+
+    @Override
+    protected void onReset() {
+        mLoader.reset();
+    }
+}