@Override
        public void packageDeleted(String packageName, int returnCode) {
            if (returnCode != PackageManager.DELETE_SUCCEEDED) {
                ProvisionLogger.logw(
                        "Could not finish the provisioning: package deletion failed");
                mCallback.onError();
                return;
            }
            int currentPackageCount = mPackageCount.decrementAndGet();
            if (currentPackageCount == 0) {
                ProvisionLogger.logi("All non-required system apps with launcher icon, "
                        + "and all disallowed apps have been uninstalled.");
                mCallback.onSuccess();
            }
        }
Runs the next task when all packages have been deleted or shuts down the activity if package
deletion fails.
engine/src/main/java/com/oasisfeng/island/provisioning/task/DeleteNonRequiredAppsTask.java