[SIM Dialog Migration] Migrate SIM enable dialog from LPA to Settings

Migrates SIM enabling and DSDS dialog from LPA to Settings.
Design: https://docs.google.com/document/d/1wb5_hoBkZVbkXGNWHbx4Jf61swjfxsJzkytiTzJosYo/edit?usp=sharing
Bug: 160819390
Test: Manually tested eSIM profile enabling.

Change-Id: I9ce690a1594adfc90b62840819237acd54418469

src/com/android/settings/AsyncTaskSidecar.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2020 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;
+
+import android.os.AsyncTask;
+
+import androidx.annotation.Nullable;
+
+import com.android.settingslib.utils.ThreadUtils;
+
+import java.util.concurrent.Future;
+
+/** A {@link SidecarFragment} which uses an {@link AsyncTask} to perform background work. */
+public abstract class AsyncTaskSidecar<Param, Result> extends SidecarFragment {
+
+    private Future<Result> mAsyncTask;
+
+    @Override
+    public void onDestroy() {
+        if (mAsyncTask != null) {
+            mAsyncTask.cancel(true /* mayInterruptIfRunning */);
+        }
+
+        super.onDestroy();
+    }
+
+    /**
+     * Executes the background task.
+     *
+     * @param param parameters passed in from {@link #run}
+     */
+    protected abstract Result doInBackground(@Nullable Param param);
+
+    /** Handles the background task's result. */
+    protected void onPostExecute(Result result) {}
+
+    /** Runs the sidecar and sets the state to RUNNING. */
+    public void run(@Nullable final Param param) {
+        setState(State.RUNNING, Substate.UNUSED);
+
+        if (mAsyncTask != null) {
+            mAsyncTask.cancel(true /* mayInterruptIfRunning */);
+        }
+
+        mAsyncTask =
+                ThreadUtils.postOnBackgroundThread(
+                        () -> {
+                            Result result = doInBackground(param);
+                            ThreadUtils.postOnMainThread(() -> onPostExecute(result));
+                        });
+    }
+}