Merge "Add CombinedMessageQueue#mNextBarrierToken" into main

    // queue for async messages when inserting a message at the tail.

    private int mLegacyAsyncMessageCount;

    // The next barrier token.

    // Barriers are indicated by messages with a null target whose arg1 field carries the token.

    @UnsupportedAppUsage

    private int mLegacyNextBarrierToken;

    /*

     * Select between two implementations of message queue. The legacy implementation is used

     * by default as it provides maximum compatibility with applications and tests that

        // Enqueue a new sync barrier token.

        // We don't need to wake the queue because the purpose of a barrier is to stall it.

        if (sForceConcurrent) {

            final int token = mNextBarrierToken.getAndIncrement();

            final int token = mNextBarrierTokenAtomic.getAndIncrement();

            // b/376573804: apps and tests may expect to be able to use reflection

            // to read this value. Make some effort to support this legacy use case.

            mNextBarrierToken = token + 1;

            final Message msg = Message.obtain();

            msg.markInUse();

        }

        synchronized (this) {

            final int token = mLegacyNextBarrierToken++;

            final int token = mNextBarrierToken++;

            final Message msg = Message.obtain();

            msg.markInUse();

            msg.when = when;

    // The next barrier token.

    // Barriers are indicated by messages with a null target whose arg1 field carries the token.

    private final AtomicInteger mNextBarrierToken = new AtomicInteger(1);

    private final AtomicInteger mNextBarrierTokenAtomic = new AtomicInteger(1);

    // Must retain this for compatibility reasons.

    @UnsupportedAppUsage

    private int mNextBarrierToken;

    /* Protects mNextIsDrainingStack */

    private final ReentrantLock mDrainingLock = new ReentrantLock();