Moving some initializations to the background thread

HandlerThread.getLooper blocks until the thread is ready. Instead
moving all looper dependency to the new thread itself.

Change-Id: I240e8c56b855a991433a7fe93875059e6dab146b

src/com/android/launcher3/util/BgObjectWithLooper.java

@@ -0,0 +1,46 @@
+/*
+ * 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.launcher3.util;
+
+import android.os.Looper;
+
+import androidx.annotation.WorkerThread;
+
+/**
+ * Utility class to define an object which does most of it's processing on a
+ * dedicated background thread.
+ */
+public abstract class BgObjectWithLooper {
+
+    /**
+     * Start initialization of the object
+     */
+    public final void initializeInBackground(String threadName) {
+        new Thread(this::runOnThread, threadName).start();
+    }
+
+    private void runOnThread() {
+        Looper.prepare();
+        onInitialized(Looper.myLooper());
+        Looper.loop();
+    }
+
+    /**
+     * Called on the background thread to handle initialization
+     */
+    @WorkerThread
+    protected abstract void onInitialized(Looper looper);
+}