test: add fixme test for binding called from pagehide in chromium

[Dmitry Gozman (dgozman)]

Summary

• Adds a test that calls an exposed binding from a pagehide handler while navigating away. Passes in Firefox and WebKit.
• Marked fixme in Chromium: with RenderDocument, the navigation swaps the frame host and Chromium never sends Runtime.bindingCalled (nor Runtime.consoleAPICalled) for the old document's pagehide/visibilitychange/unload handlers.

References #43064

[github-actions]

Test results for "tests 1"

7 flaky

⚠️ [chromium-library] › library/browsercontext-page-event.spec.ts:173 › should work with Ctrl-clicking `@frozen-time-library-chromium-linux`
⚠️ [chromium-library] › library/browsercontext-page-event.spec.ts:173 › should work with Ctrl-clicking `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/video.spec.ts:762 › screencast › should work with video+trace `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/browsercontext-page-event.spec.ts:160 › should work with Shift-clicking `@realtime-time-library-chromium-linux`
⚠️ [chromium-library] › library/chromium/chromium.spec.ts:213 › should intercept service worker requests (main and within) `@chromium-ubuntu-22.04-node24`
⚠️ [firefox-library] › library/browsercontext-cookies-third-party.spec.ts:257 › third party 'Partitioned;' cookies `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-library] › library/browsercontext-cookies-third-party.spec.ts:470 › top level 'Partitioned;' cookie and same origin iframe `@firefox-ubuntu-22.04-node20`

52538 passed, 1276 skipped

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Merge workflow run.

[github-actions]

Test results for "MCP"

3 failed
❌ [firefox] › mcp/cli-core.spec.ts:57 › click link @mcp-windows-latest-firefox
❌ [firefox] › mcp/cli-drag.spec.ts:53 › drop files and data onto an element @mcp-windows-latest-firefox
❌ [webkit] › mcp/http.spec.ts:92 › http transport browser lifecycle (isolated) @mcp-ubuntu-latest-webkit

8934 passed, 1489 skipped

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Merge workflow run.

[github-actions]

Hi, I'm the Playwright bot and I took a first look at the CI failures.

🟢 All three failures are confirmed pre-existing flakes — this PR is clear

This PR only adds a library test for an exposed binding during pagehide; it does not touch MCP code. Each failing MCP test has failed with the same project and bot on unrelated changes.

Details

Overall: the "tests 1" report has no real failures; its seven flaky tests passed on retry. The MCP report has three failures, all in code paths outside this one-file test-only diff.

Pre-existing flake / infra

• [firefox] › mcp/cli-core.spec.ts:57 › click link (mcp-windows-latest-firefox) — the click timed out after "performing click action". This exact test and bot failed on unrelated fix(webkit): use native checkVisibility for element visibility #42971 and chore(video): list ffmpeg args one option per line #43024; the CI results history cited on fix(webkit): use native checkVisibility for element visibility #42971 recorded 5 failures in 725 runs, including main pushes.
• [firefox] › mcp/cli-drag.spec.ts:53 › drop files and data onto an element (mcp-windows-latest-firefox) — this exact test and bot failed on unrelated fix(chromium): dispose worker sessions when their frame session is disposed #42282, feat(webkit): roll to r2359 #42493, and fix(trace-viewer): reject unsafe snapshot tag names #42712, as well as multiple main pushes. The historical results on fix(chromium): dispose worker sessions when their frame session is disposed #42282 show it failing on 2 of 558 runs and passing the other 556.
• [webkit] › mcp/http.spec.ts:92 › http transport browser lifecycle (isolated) (mcp-ubuntu-latest-webkit) — timed out after 30 seconds here, and the exact same test and bot failed on unrelated test: crashed page should still be in the list of pages #43043 one day earlier.

The added browsercontext-expose-function.spec.ts case runs in the library workflow and cannot affect these separate MCP jobs.

_{Triaged by the Playwright bot - agent run}