Use main thread executor in the split controller

import android.content.Intent;

import android.content.res.Configuration;

import android.os.Bundle;

import android.os.Handler;

import android.os.IBinder;

import android.os.Looper;

import android.window.TaskFragmentAppearedInfo;

import android.window.TaskFragmentInfo;

import android.window.WindowContainerTransaction;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.Executor;

/**

 * Main controller class that manages split states and presentation.

    private SplitOrganizerCallback mSplitOrganizerCallback;

    public SplitController() {

        mPresenter = new SplitPresenter(ActivityThread.currentActivityThread().getExecutor(),

                this);

        mPresenter = new SplitPresenter(new MainThreadExecutor(), this);

        // Register a callback to be notified about activities being created.

        ActivityThread.currentActivityThread().getApplication().registerActivityLifecycleCallbacks(

                new LifecycleCallbacks());

        public void onActivityDestroyed(Activity activity) {

        }

    }

    /** Executor that posts on the main application thread. */

    private static class MainThreadExecutor implements Executor {

        private final Handler handler = new Handler(Looper.getMainLooper());

        @Override

        public void execute(Runnable r) {

            handler.post(r);

        }

    }

}