fix(preview): apply native viewport sizes without resize hangs

[kr4chinin]

Problem

Follow-up fixes are pushed to fix/preview-viewport-upstream at 720a677b945b571c9681aba820be3fe9eb886a44. This closed PR still records c3dd8ae9, pending maintainer reconsideration and reopening.

preview_resize can time out because the stored viewport, rendered layout and native guest disagree. The toolbar has the same mismatch: at host zoom level 0.5, the installed Nightly displays 427x925 after selecting the 390x844 iPhone preset, and 460x658 after entering 420x600.

The native guest now uses the selected viewport. Returning to fill clears the override. Failed or late requests preserve newer viewport state.

Closes #3712
Closes #12319
Closes #10525

Related: #13540 and #13610. The fix removes the resize-timeout trigger, without claiming to fix general host failover or the separate GPU-memory lifecycle problem.

UI verification

These captures exercise the real packaged Browser panel with a local HTTP page showing innerWidth and innerHeight. Both versions use separate temporary profiles, host zoom level 0.5 (about 109.5%), and guest zoom 100%. Before: Nightly 99e08526e5ec. After: 720a677b945b571c9681aba820be3fe9eb886a44.

Flow	Before	After
iPhone 12 Pro, 390x844
Freeform, 420x600
Return to fill

The additional capture and recording (53 seconds) use guest zoom 80% with the same non-default host zoom. The recording shows preset selection, freeform sizing and return to fill through the toolbar.

toolbar-resize.mp4

Change

• Convert requested CSS dimensions to CDP's integer DIP dimensions using the document's effective zoom. Reconcile after zoom, navigation, guest replacement and debugger reattachment. Preserve the captured automation control check through retries so human takeover aborts the resize.
• Give server viewport mutations per-tab revisions and compare-and-swap rollback. For older servers missing rollback metadata, capture the predecessor when the serialized mutation begins and compensate only while that client mutation still owns the viewport. Those older servers cannot provide atomic cross-client rollback.
• Bound native and rendered readiness waits, including a stalled layout-metrics query or executeJavaScript. At the minimum supported guest zoom 25%, integer DIP rounding can produce 392x844 for 390x844. Fixed-mode readiness therefore allows at most 2 CSS pixels while still checking the exact setting and declared size, and returns the actual measurement. Fill keeps its 1 pixel tolerance.

Based on Theo Browne's #8469 and Guilherme Barros's #7303, credited in the original commit. These links establish provenance, not approval of this branch.

Verification

On 720a677b945b571c9681aba820be3fe9eb886a44: 277 focused tests in 12 suites passed, along with scoped web/desktop typechecks, lint/format, the desktop build and local packaging. Independent follow-up review has no remaining actionable findings.

Native Electron probes and raw measurements: 132 records (12 baselines and 120 checked post-operation measurements) cover actual HTTP navigation and about:blank, host zoom levels 0 and 0.5, guest factors 1, 0.8 and 1.25, resizing, clearing, zoom changes, navigation and reload. A separate low-zoom run records the rounding above. The earlier blank-only probe did not exercise effective HTTP-page zoom, so its results are limited to that document.

The unchanged PreviewAutomationHosts.test.tsx status test has 5 passes and 1 failure on the original PR head c3dd8ae9 too: its empty mocked list clears automation-tab. Linux/Windows runtime checks and a full collaborative-browser pass on an installed patched build remain unverified. The running T3 installation was not modified. External review/CI approval is pending maintainer reconsideration of this closed PR.

Made with GPT-6.1-Sol using the Codex harness in T3 Code.

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[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This is a 25-file, 2,599-line change that substantially alters viewport application, automation deadlines, rollback, and cross-layer state ordering across desktop, web, and server paths. The unresolved findings also identify stale-control and mixed-version rollback risks that require human assessment.

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[juliusmarminge]

Note

This comment is posted by Julius' dot

Closing for missing UI verification. This changes the visible preview's toolbar resizing and return to fill mode, but the PR explicitly omits before/after screenshots and a recording. The native probe checks guest dimensions without exercising that UI flow. Add before/after screenshots and a short recording showing fixed or preset resizing and return to fill at non-default zoom, then request reconsideration.

[kr4chinin]

@juliusmarminge The updated PR body contains seven before/after screenshots and a 53-second recording from the packaged Browser panel. The recording shows preset selection, freeform sizing and return to fill at host zoom level 0.5 and guest zoom 80%. Both Macroscope findings have been fixed, replied to and resolved. The real HTTP-page check uncovered a further zoom conversion issue, which is fixed with zoom/navigation/reload regressions.

The follow-up branch is pushed at 720a677b945b571c9681aba820be3fe9eb886a44. The closed PR still records c3dd8ae9, so the follow-up diff is linked explicitly. 277 focused tests, scoped static checks, the desktop build/package and the isolated native/runtime UI checks pass. CI and fresh external approval remain pending.

Could you reconsider and reopen this PR for review of the updated branch?