/**
 * @license
 * Copyright 2016 Google Inc. All rights reserved.
 *
 * 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.
 */
/**
 * `BlockingElements` manages a stack of elements that inert the interaction
 * outside them. The top element is the interactive part of the document.
 * The stack can be updated with the methods `push, remove, pop`.
 */
export interface BlockingElements {
    /**
     * Call this whenever this object is about to become obsolete. This empties
     * the blocking elements
     */
    destructor(): void;
    /**
     * The top blocking element.
     */
    top: HTMLElement | null;
    /**
     * Adds the element to the blocking elements.
     */
    push(element: HTMLElement): void;
    /**
     * Removes the element from the blocking elements. Returns true if the
     * element was removed.
     */
    remove(element: HTMLElement): boolean;
    /**
     * Remove the top blocking element and returns it.
     */
    pop(): HTMLElement | null;
    /**
     * Returns if the element is a blocking element.
     */
    has(element: HTMLElement): boolean;
}
export interface DocumentWithBlockingElements extends Document {
    $blockingElements: BlockingElements;
}