/**
 * A style manager adds style elements when styles are registered,
 * and removes them when they are unregistered.
 *
 * Using a custom style manager allows control over how style
 * elements are injected into the DOM.
 *
 * _MUST REMAIN STABLE BETWEEN VERSIONS!_
 */
export interface IStyleManager {
    /**
     * Called when a new style element should be added to the DOM.
     *
     * The `replacedCacheKey` is the key of the style that the new
     * style is derived from, which should be used to insert the new
     * style in proximity to the previous style, so that precedence is
     * not drastically affected when a style is mutated.
     */
    register(cacheKey: string, cssText: string, replacedCacheKey?: string): void;
    /**
     * Called when an existing style element should be removed from
     * the DOM.
     */
    unregister(cacheKey: string): void;
}