fix(chromium): emit serviceworker event on MV3 SW stop/restart lifecycle

[shairoth12]

Fixes #39475

Problem

When a Manifest V3 extension's service worker stops and restarts, Chrome reuses the same CDP target ID. This means no Target.attachedToTarget event is fired, so Playwright never creates a new CRServiceWorker instance and the 'serviceworker' event is never emitted on the BrowserContext. The original Worker reference remains in context.serviceWorkers() with a stale execution context, causing any subsequent evaluate() to throw.

Fix

Restart detection is now handled at the execution-context level inside CRServiceWorker, which already holds the CDP session for the reused target.

Two new fields track the current context lifecycle:

• _currentContextId — the execution context ID currently in use
• _currentContextDestroyed — set to true by Runtime.executionContextDestroyed or Runtime.executionContextsCleared

The Runtime.executionContextCreated listener (previously session.once) is now persistent. When a new context arrives after the previous one was destroyed, _handleRestart() is called:

1. The old Worker is retired (emits Worker.Events.Close, closes its scope, removes it from browser._serviceWorkers) — without disposing the CDP session, since the new worker reuses it
2. A fresh CRServiceWorker is created with the same session and target ID
3. The 'serviceworker' event is emitted on the BrowserContext

A same-ID re-send from Runtime.enable (context still alive) is correctly ignored via the _currentContextDestroyed flag.

Changes

• packages/playwright-core/src/server/chromium/crServiceWorker.ts — restart detection and handling
• packages/playwright-core/src/server/chromium/crBrowser.ts — pass targetId to CRServiceWorker constructor
• tests/library/chromium/extensions.spec.ts — new test for stop/restart lifecycle; timing fix to register waitForEvent before triggering the cycle
• docs/src/chrome-extensions-js-python.md — new "Testing extension reload" section
• docs/src/api/class-browsercontext.md — updated serviceworker event docs with timing guidance

[shairoth12]

@microsoft-github-policy-service agree