/**
 * CdpSessionUrlTracker — sniffs the Chrome→Client leg of the CDP WebSocket
 * proxy and maintains a `sessionId -> currentUrl` map keyed the same way
 * navigation-watcher.ts keys its session state. The map feeds the Client→
 * Chrome unmask gate (cdp-unmask.ts) so per-frame unmasking is scoped to
 * the target tab's actual current URL.
 *
 * Three CDP events feed the tracker:
 *   - `Target.attachedToTarget`    → seed via `params.sessionId` + `params.targetInfo.url`
 *   - `Target.targetInfoChanged`   → keyed by `params.targetInfo.targetId`; updates
 *     every session pointing at that target
 *   - `Page.frameNavigated` (root) → `sessionId` lives at the wire-frame top level;
 *     only the root frame (no parentId) updates the session url
 *
 * `Target.detachedFromTarget` clears the entry. Everything else is a no-op.
 *
 * Hostname resolution is done lazily via `getHostname(sessionId)`. Empty,
 * un-parseable, or `about:blank`-style URLs fail closed (return null).
 */
export interface CdpSessionUrlTracker {
    observeChromeToClient(frame: unknown): void;
    getHostname(sessionId: string | undefined): string | null;
    getUrl(sessionId: string | undefined): string | null;
    size(): number;
    clear(): void;
}
export declare function createCdpSessionUrlTracker(): CdpSessionUrlTracker;