Use a Handler for ProtoLogging instead of an ExecutorService

import android.annotation.NonNull;

import android.annotation.Nullable;

import android.internal.perfetto.protos.Protolog.ProtoLogViewerConfig.MessageData;

import android.os.Handler;

import android.os.HandlerThread;

import android.os.RemoteException;

import android.os.ServiceManager;

import android.os.ShellCommand;

import java.io.PrintWriter;

import java.io.StringWriter;

import java.lang.StringBuilder;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.Set;

import java.util.TreeMap;

import java.util.UUID;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.LinkedBlockingQueue;

import java.util.concurrent.ThreadPoolExecutor;

import java.util.concurrent.TimeUnit;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.locks.Lock;

import java.util.concurrent.locks.ReadWriteLock;

import java.util.concurrent.locks.ReentrantLock;

import java.util.concurrent.locks.ReentrantReadWriteLock;

/**

    @NonNull

    private final ReadWriteLock mConfigUpdaterLock = new ReentrantReadWriteLock();

    private final Lock mBackgroundServiceLock = new ReentrantLock();

    // NOTE: This is a single-thread executor configured with a ThreadPoolExecutor and a

    // LinkedBlockingQueue. This ensures that tasks are executed in FIFO (First-In, First-Out)

    // order, which is crucial for operations like connecting to the configuration service before

    // other logging activities, and synchronizing queued logging tasks on tracing start and stop.

    // Configuration:

    //   corePoolSize: 1 (single thread)

    //   maximumPoolSize: 1 (single thread)

    //   keepAliveTime: 0L (threads do not time out)

    //   workQueue: LinkedBlockingQueue (unbounded, FIFO)

    @NonNull

    private final HandlerThread mBackgroundThread;

    // Handler associated with the mBackgroundThread, ensuring tasks are processed sequentially

    // on a single background thread. This is crucial for operations like connecting to the

    // configuration service before other logging activities, and synchronizing queued

    // logging tasks on tracing start and stop.

    @VisibleForTesting

    public final ExecutorService mBackgroundLoggingService =

            new ThreadPoolExecutor(1, 1,

                    0L, TimeUnit.MILLISECONDS,

                    new LinkedBlockingQueue<>());

    @NonNull

    public final Handler mBackgroundHandler;

    // Set to true once this is ready to accept protolog to logcat requests.

    private boolean mLogcatReady = false;

        mCacheUpdater = cacheUpdater;

        mConfigurationService = configurationService;

        mBackgroundThread = new HandlerThread("ProtoLogBackground");

        mBackgroundThread.start();

        mBackgroundHandler = Handler.createAsync(mBackgroundThread.getLooper());

        registerGroupsLocally(groups);

    }

        Objects.requireNonNull(mConfigurationService,

                "A null ProtoLog Configuration Service was provided!");

        mBackgroundLoggingService.execute(() -> {

        mBackgroundHandler.post(() -> {

            try {

                var args = createConfigurationServiceRegisterClientArgs();

        mDataSource.unregisterOnStopCallback(this);

        if (android.tracing.Flags.clientSideProtoLogging()) {

            mBackgroundLoggingService.execute(() -> {

            mBackgroundHandler.post(() -> {

                try {

                    mConfigurationService.unregisterClient(this);

                } catch (RemoteException e) {

                }

            });

        }

        mBackgroundLoggingService.shutdown();

        mBackgroundThread.quitSafely();

    }

    @NonNull

            } else {

                stacktrace = null;

            }

            mBackgroundServiceLock.lock();

            try {

                mBackgroundLoggingService.execute(() -> {

            mBackgroundHandler.post(() -> {

                try {

                    logToProto(logLevel, group, message, args, tsNanos,

                            stacktrace);

                    throw new RuntimeException(sb.toString(), e);

                }

            });

            } finally {

                mBackgroundServiceLock.unlock();

            }

        }

        if (group.isLogToLogcat()) {

            logToLogcat(group.getTag(), logLevel, message, args);

    }

    private void waitForExistingBackgroundTasksToComplete() {

        try {

            this.mBackgroundLoggingService.submit(() -> {

        final CountDownLatch latch = new CountDownLatch(1);

        mBackgroundHandler.post(() -> {

            Log.i(LOG_TAG, "Completed all pending background tasks");

            }).get();

        } catch (InterruptedException | ExecutionException e) {

            latch.countDown();

        });

        try {

            latch.await();

        } catch (InterruptedException e) {

            Log.e(LOG_TAG, "Failed to wait for tracing service background tasks to complete", e);

            Thread.currentThread().interrupt(); // Preserve interrupt status

        }

    }

        // Load in background to avoid delay in boot process.

        // The caveat is that any log message that is also logged to logcat will not be

        // successfully decoded until this completes.

        mBackgroundLoggingService.execute(() -> {

        mBackgroundHandler.post(() -> {

            mViewerConfigReader.loadViewerConfig(groupsLoggingToLogcat.toArray(new String[0]));

            readyToLogToLogcat();

        });

                    sProtoLog.isProtoEnabled());

            // Submit a task that will block the executor queue.

            sProtoLog.mBackgroundLoggingService.execute(() -> {

            sProtoLog.mBackgroundHandler.post(() -> {

                try {

                    blockingTaskStartedExecution.set(true);

                    processingHasStartedLatch.countDown(); // Signal that this task has started

            allowProcessingToContinueLatch.countDown();

            // Stop tracing immediately. The implementation should wait for the

            // mBackgroundLoggingService to process all queued messages (including the

            // mBackgroundHandler to process all queued messages (including the

            // now-unblocked first task and all subsequent log messages).

        } finally {

            // Ensure the latch is always counted down if an exception occurred before stop,