Merge "Fix an errorprone for GuardedBy warning"

    @BinderThread

    @Override

    public void reportPerceptibleAsync(IBinder windowToken, boolean perceptible) {

        Binder.withCleanCallingIdentity(() -> {

            Objects.requireNonNull(windowToken, "windowToken must not be null");

            synchronized (ImfLock.class) {

                if (mCurFocusedWindow != windowToken || mCurPerceptible == perceptible) {

                    return;

                }

                mCurPerceptible = perceptible;

            Binder.withCleanCallingIdentity(() ->

                    updateSystemUiLocked(mImeWindowVis, mBackDisposition));

                updateSystemUiLocked();

            }

        });

    }

    @GuardedBy("ImfLock.class")