/**
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { EventEmitter } from './EventEmitter';
/**
 * @extends {EventEmitter}
 */
export declare class VisibilityMonitor extends EventEmitter {
    private visible_;
    static getInstance(): VisibilityMonitor;
    constructor();
    /**
     * @param {!string} eventType
     * @return {Array.<boolean>}
     */
    getInitialEvent(eventType: string): boolean[];
}
