fix(chromium): stop disabling BoundaryEventDispatchTracksNodeRemoval

[Yury Semikhatsky (yury-s)]

Summary

• Stop disabling the Chrome 144 BoundaryEventDispatchTracksNodeRemoval feature, so pages under test get the same boundary event semantics as real Chrome.
• Mark cli-codegen-1.spec.ts "should record slider" as fixme on linux chromium, where it stays ~10% flaky with the feature enabled.

Chromium does not restore a node's hover claim when it is re-attached in the same task, so a node re-appended out from under the pointer never gets its mouseout. Filed upstream as https://crbug.com/548251131.

The feature was originally disabled in 622ddd8 for #38568, which is the slider recording flake now marked fixme.

Fixes #42270

[github-actions]

Test results for "MCP"

3 failed
❌ [chrome] › mcp/config.spec.ts:203 › chromiumSandbox › --sandbox enables the sandbox @mcp-ubuntu-latest-chrome
❌ [chrome] › mcp/annotate.spec.ts:349 › should annotate when context has no fixed viewport @mcp-windows-latest-chrome
❌ [msedge] › mcp/annotate.spec.ts:137 › should abort MCP annotation when last screenshot is removed @mcp-windows-latest-msedge

8107 passed, 1341 skipped

---

Merge workflow run.

[github-actions]

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

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

The MCP report has 3 failures, all in areas this PR doesn't touch. This PR only stops disabling the Chromium BoundaryEventDispatchTracksNodeRemoval feature (pointer/boundary-event semantics) and marks the slider codegen test fixme — none of the failing tests exercise that path. Each one also fails on SHAs this PR can't be responsible for.

Details

Pre-existing flake / infra

• [chrome] › mcp/config.spec.ts:203 › chromiumSandbox › --sandbox enables the sandbox (mcp-ubuntu-latest-chrome) — Linux-only flake, unrelated to the diff. In the test-results DB the exact same test on the same bot also failed on main (push, sha b856094e, this PR's base) and on PR feat(browserContext): add windowState option #42286 (fix-1086, sha 548642df), while every windows/macos chrome run passed. Sandbox startup on Linux has nothing to do with boundary-event dispatch.
• [chrome] › mcp/annotate.spec.ts:349 › should annotate when context has no fixed viewport — pre-existing flake. Across the DB it flips verdict on unrelated SHAs: chrome 1/734, firefox 3/721, msedge 1/587, with retries rescuing several runs; chromium and webkit are green. Viewport/annotation flow, untouched by this PR.
• [msedge] › mcp/annotate.spec.ts:137 › should abort MCP annotation when last screenshot is removed — pre-existing flake. Same story: msedge 4/587, chrome 1/734, firefox 1/720 failing on unrelated SHAs (some rescued on retry), chromium and webkit green.

The triggering "tests 1" run was also cancelled, so those counts are incomplete — but nothing there points at this PR either.

_{Triaged by the Playwright bot - agent run}

[github-actions]

Test results for "tests 1"

Warning

The triggering workflow run ended with status cancelled. Results below may be incomplete — blob reports from cancelled or timed-out shards are missing, so passing/failing counts do not reflect the full test suite.

12 flaky

⚠️ [chromium-library] › library/global-fetch.spec.ts:293 › should return security details from response `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/har.spec.ts:639 › should have security details `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/global-fetch.spec.ts:293 › should return security details from response `@realtime-time-library-chromium-linux`
⚠️ [chromium-library] › library/har.spec.ts:639 › should have security details `@realtime-time-library-chromium-linux`
⚠️ [chromium-library] › library/global-fetch.spec.ts:293 › should return security details from response `@chromium-ubuntu-22.04-node20`
⚠️ [chromium-library] › library/har.spec.ts:639 › should have security details `@chromium-ubuntu-22.04-node20`
⚠️ [chromium-library] › library/global-fetch.spec.ts:293 › should return security details from response `@chromium-ubuntu-22.04-node22`
⚠️ [chromium-library] › library/har.spec.ts:639 › should have security details `@chromium-ubuntu-22.04-node22`
⚠️ [firefox-library] › library/global-fetch.spec.ts:293 › should return security details from response `@firefox-ubuntu-22.04-node20`
⚠️ [firefox-library] › library/har.spec.ts:639 › should have security details `@firefox-ubuntu-22.04-node20`
⚠️ [webkit-library] › library/global-fetch.spec.ts:293 › should return security details from response `@webkit-ubuntu-22.04-node20`
⚠️ [webkit-library] › library/har.spec.ts:639 › should have security details `@webkit-ubuntu-22.04-node20`

39790 passed, 857 skipped

---

Merge workflow run.