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Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)"#186266

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Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)"#186266
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Reverts: #186166

Initiated by: hellohuanlin

Reason for reverting: This caused a crash due to using the incorrect time in G3, so reverting it.

Original PR Author: cbracken

Reviewed By: {hellohuanlin}

This change reverts the following previous change:
Migrates FlutterVSyncClient from a hybrid C++/Obj-C implementation to a pure Objective-C implementation by removing C++ types from its interface and implementation.

Previously, FlutterVSyncClient stored a C++
flutter::VsyncWaiter::Callback and used a temporary std::unique_ptr<flutter::FrameTimingsRecorder> to propagate vsync timestamps. This was redundant:

  • FlutterVSyncClient allocated a temporary FrameTimingsRecorder and recorded vsync times.
  • It passed this to a C++ lambda wrapper.
  • The lambda extracted the start/target times as seconds and passed them to the Obj-C block callback.
  • The temporary recorder was immediately discarded.
  • VsyncWaiterIOS converted the seconds back to fml::TimePoint.
  • VsyncWaiter::FireCallback allocated another FrameTimingsRecorder and recorded the same times again.

We now:

  • manage the callback as pure Obj-C block that accepts raw CFTimeInterval (double seconds) directly from CADisplayLink.
  • Remove the redundant FrameTimingsRecorder and C++ lambda wrapper.
  • Rely solely on VsyncWaiter::FireCallback to handle the final FrameTimingsRecorder creation and recording, which it already does.

No test changes because this introduces no semantic change and is covered by existing tests recently added in:
https://github.com/flutter/flutter/blob/master/engine/src/flutter/shell/platform/darwin/ios/framework/Source/VSyncClientTest.swift

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@auto-submit auto-submit Bot added the revert of Bot Only: Tracking label for bot. Tracks new revert of pull requests. label May 8, 2026
@auto-submit auto-submit Bot requested a review from a team as a code owner May 8, 2026 18:28
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It looks like this pull request may not have tests. Please make sure to add tests or get an explicit test exemption before merging.

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. If you believe this PR qualifies for a test exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!). The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

@github-actions github-actions Bot added platform-ios iOS applications specifically engine flutter/engine related. See also e: labels. team-ios Owned by iOS platform team labels May 8, 2026
@auto-submit auto-submit Bot removed the revert of Bot Only: Tracking label for bot. Tracks new revert of pull requests. label May 8, 2026
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auto-submit Bot commented May 8, 2026

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auto label is removed for flutter/flutter/186266, Failed to enqueue flutter/flutter/186266 with HTTP 400: Pull request Required status check "Merge Queue Guard" is expected..

@chingjun chingjun added the CICD Run CI/CD label May 8, 2026
@hellohuanlin hellohuanlin added the autosubmit Merge PR when tree becomes green via auto submit App label May 8, 2026
@auto-submit auto-submit Bot removed the autosubmit Merge PR when tree becomes green via auto submit App label May 8, 2026
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autosubmit label was removed for flutter/flutter/186266, because - The status or check suite cla/google has failed. Please fix the issues identified (or deflake) before re-applying this label.

cbracken added a commit to cbracken/flutter that referenced this pull request May 13, 2026
Adds doc comments for FlutterVSyncClient and FlutterDisplayLink as well
as implementation notes in the -[FlutterDisplayLink onDisplayLink:]
callback.

Related PRs:
* flutter#186166
* flutter#186266
cbracken added a commit to cbracken/flutter that referenced this pull request May 13, 2026
Adds doc comments for FlutterVSyncClient and FlutterDisplayLink as well
as implementation notes in the -[FlutterDisplayLink onDisplayLink:]
callback.

Related PRs:
* flutter#186166
* flutter#186266
cbracken added a commit to cbracken/flutter that referenced this pull request May 13, 2026
Adds doc comments for FlutterVSyncClient and FlutterDisplayLink as well
as implementation notes in the -[FlutterDisplayLink onDisplayLink:]
callback.

Related PRs:
* flutter#186166
* flutter#186266
auto-submit Bot pushed a commit to flutter/packages that referenced this pull request May 14, 2026
Roll Flutter from 707dbc0420a3 to 23f6f5853f50 (149 revisions)

flutter/flutter@707dbc0...23f6f58

2026-05-12 737941+loic-sharma@users.noreply.github.com Add 'cp: review' label to the manual cherrypick process (flutter/flutter#186158)
2026-05-12 engine-flutter-autoroll@skia.org Roll Packages from 19ec8b8 to 93cbed6 (3 revisions) (flutter/flutter#186401)
2026-05-12 30870216+gaaclarke@users.noreply.github.com Removes SDF option for macOS (always enabled) (flutter/flutter#186265)
2026-05-12 nico.reiab@gmail.com docs: fix typos in flutter_tools comments (flutter/flutter#186321)
2026-05-12 15619084+vashworth@users.noreply.github.com Pass XcodeBasedProject instead of String to functions in XcodeProjectInterpreter (flutter/flutter#186378)
2026-05-12 jason-simmons@users.noreply.github.com Update iOS scenario app test goldens to match changes from flutter/flutter#182662 (flutter/flutter#186390)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from ad0aff15b9fa to 77a21bc723dc (2 revisions) (flutter/flutter#186396)
2026-05-12 32538273+ValentinVignal@users.noreply.github.com Migrate focus_node.unfocus.0.dart to use `RadioGroup` (flutter/flutter#183979)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from 91d3c1e730af to ad0aff15b9fa (7 revisions) (flutter/flutter#186391)
2026-05-12 bdero@google.com [Flutter GPU] Allow customizing the vertex layout on a RenderPipeline (flutter/flutter#186310)
2026-05-12 97480502+b-luk@users.noreply.github.com Fix `EmbedderTest.CanRenderTextWithImpellerMetal` test breakage (flutter/flutter#186262)
2026-05-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from rFhU-YPqdCRCtCz7b... to z7ICmPtn4hspu02zk... (flutter/flutter#186384)
2026-05-12 bdero@google.com [Impeller] GLES: lazily allocate texture mip levels on first per-level write (flutter/flutter#186302)
2026-05-12 bdero@google.com [Android] Propagate --enable-flutter-gpu Intent extra to engine args (flutter/flutter#186298)
2026-05-11 47866232+chunhtai@users.noreply.github.com [ci] update no-response workflow to also look for old label name in e… (flutter/flutter#186373)
2026-05-11 bdero@google.com [ImpellerC] Write a depfile when --shader-bundle is in use (flutter/flutter#186341)
2026-05-11 nico.reiab@gmail.com docs: fix doubled-word typos in comments (flutter/flutter#186320)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 32281401997e to 91d3c1e730af (4 revisions) (flutter/flutter#186368)
2026-05-11 15619084+vashworth@users.noreply.github.com Show SwiftPM warnings right before iOS/macOS build (flutter/flutter#185984)
2026-05-11 15619084+vashworth@users.noreply.github.com Convert rebuilding-flutter-tool script to dart (flutter/flutter#185089)
2026-05-11 15619084+vashworth@users.noreply.github.com Use Xcode's LLDB (flutter/flutter#186273)
2026-05-11 mr-peipei@web.de Remove `currentMainUri` from `generateMainDartWithPluginRegistrant` (flutter/flutter#185907)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 2514f6b5f92b to 32281401997e (1 revision) (flutter/flutter#186349)
2026-05-11 engine-flutter-autoroll@skia.org Roll Packages from 92552b1 to 19ec8b8 (4 revisions) (flutter/flutter#186350)
2026-05-11 1063596+reidbaker@users.noreply.github.com Check for absolute paths in skills.  (flutter/flutter#185632)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 9fb7d2814642 to 2514f6b5f92b (1 revision) (flutter/flutter#186347)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 8cafb209e836 to 9fb7d2814642 (4 revisions) (flutter/flutter#186335)
2026-05-10 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from sOBiPJb0xznDBZlf5... to rFhU-YPqdCRCtCz7b... (flutter/flutter#186328)
2026-05-10 engine-flutter-autoroll@skia.org Roll Skia from 05a03f99c74e to 8cafb209e836 (1 revision) (flutter/flutter#186315)
2026-05-10 bdero@google.com [Impeller] Vulkan: don't drop user-supplied viewport X, Y, and depth range (flutter/flutter#185886)
2026-05-09 mbrase@google.com Update Fuchsia tests to subpackage their child components (flutter/flutter#186259)
2026-05-09 victorsanniay@gmail.com Fix SelectableText crash with inline lambda contextMenuBuilder (flutter/flutter#184990)
2026-05-09 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from 5_TnhTsHSqtCx37o6... to sOBiPJb0xznDBZlf5... (flutter/flutter#186289)
2026-05-09 engine-flutter-autoroll@skia.org Roll Skia from dc78d4bd2efb to 05a03f99c74e (2 revisions) (flutter/flutter#186283)
2026-05-09 22373191+Hari-07@users.noreply.github.com Improve non rect platform view rendering  (flutter/flutter#182662)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 31521f8508c7 to dc78d4bd2efb (1 revision) (flutter/flutter#186278)
2026-05-08 30870216+gaaclarke@users.noreply.github.com Moves wide_gamut_macos to arm64 (flutter/flutter#186214)
2026-05-08 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)" (flutter/flutter#186266)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from a00db8749edb to 31521f8508c7 (2 revisions) (flutter/flutter#186264)
2026-05-08 97480502+b-luk@users.noreply.github.com Optimize compatible `DrawDiffRoundRect` calls to use `DrawRoundRect` (flutter/flutter#186203)
2026-05-08 bdero@google.com [triage] Add Flutter GPU as a triage team (flutter/flutter#186263)
2026-05-08 dmgr@google.com doc: Unified Check-Run User manual (flutter/flutter#186210)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 5f7adf4403d6 to a00db8749edb (1 revision) (flutter/flutter#186257)
2026-05-08 engine-flutter-autoroll@skia.org Roll Packages from 0411f1d to 92552b1 (1 revision) (flutter/flutter#186256)
2026-05-08 34871572+gmackall@users.noreply.github.com Add logging to figure out jvm crashes for `hot_mode_tests` (flutter/flutter#186107)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 926c09741ce2 to 5f7adf4403d6 (3 revisions) (flutter/flutter#186242)
...
patevs pushed a commit to patevs/flutter that referenced this pull request May 16, 2026
…ink (flutter#186456)

Adds doc comments for FlutterVSyncClient and FlutterDisplayLink as well
as implementation notes in the `-[FlutterDisplayLink onDisplayLink:]`
callback.

No test changes since this is a documentation-only patch.

Related PRs:
* flutter#186166
* flutter#186266

## Pre-launch Checklist

- [X] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [X] I read the [AI contribution guidelines] and understand my
responsibilities, or I am not using AI tools.
- [X] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [X] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [X] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [X] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [X] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
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If this change needs to override an active code freeze, provide a
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**Note**: The Flutter team is currently trialing the use of [Gemini Code
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Comments from the `gemini-code-assist` bot should not be taken as
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pull Bot pushed a commit to AbhiShake1/flutter that referenced this pull request May 23, 2026
…) (flutter#186935)

Migrates `FlutterVSyncClient` from a hybrid C++/Obj-C implementation to
a pure Objective-C implementation by removing C++ types from its
interface and implementation.

Previously, `FlutterVSyncClient` stored a C++
`flutter::VsyncWaiter::Callback` and used a temporary
`std::unique_ptr<flutter::FrameTimingsRecorder>` to propagate vsync
timestamps. This was redundant:

* `FlutterVSyncClient` allocated a temporary `FrameTimingsRecorder` and
recorded vsync times.
* It passed this to a C++ lambda wrapper.
* The lambda extracted the start/target times as seconds and passed them
to the Obj-C block callback.
* The temporary recorder was immediately discarded.
* `VsyncWaiterIOS` converted the seconds back to `fml::TimePoint`.
* `VsyncWaiter::FireCallback` allocated *another* `FrameTimingsRecorder`
and recorded the same times again.

We now:
* manage the callback as pure Obj-C block that accepts raw
`CFTimeInterval` (double seconds) directly from `CADisplayLink`.
* Remove the redundant `FrameTimingsRecorder` and C++ lambda wrapper.
* Rely solely on `VsyncWaiter::FireCallback` to handle the final
`FrameTimingsRecorder` creation and recording, which it already does.

This is a re-land of flutter#186166 which was reverted in flutter#186266. That patch
failed to correctly adjust the epoch of timestamps obtained from
CoreAnimation (which uses `mach_absolute_time` under the hood) to the
epoch used by the core engine, which is built on `fml::TimePoint`, which
uses `std::chrono::steady_clock`, which uses `mach_continuous_time`
under the hood, consistent with the C++ specification's of a continuous
clock. While these two clocks start roughly synchronized at boot,
`mach_absolute_time` pauses on device sleep, whereas
`mach_continuous_time` does not.

The iOS embedder now uses timings based on CoreAnimation throughout and
translates to `fml::TimePoint` only at the engine-embedder boundary.
This is consistent with embedders based on the embedder API, such as
macOS, which does this work in `-[FlutterEngine
viewControllerViewDidLoad]` using `FlutterTimeConverter`.

Added tests for frame rate snapping/fallback. No other test changes
because this introduces no semantic change and is covered by existing
tests recently added in: flutter#186457

Issue: flutter#112232

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## Pre-launch Checklist

- [X] I read the [Contributor Guide] and followed the process outlined
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If you need help, consider asking for advice on the #hackers-new channel
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If this change needs to override an active code freeze, provide a
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**Note**: The Flutter team is currently trialing the use of [Gemini Code
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Comments from the `gemini-code-assist` bot should not be taken as
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[Contributor Guide]:
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[Flutter Style Guide]:
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[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
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[Data Driven Fixes]:
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stuartmorgan-g pushed a commit to flutter/core-packages that referenced this pull request Jun 9, 2026
Roll Flutter from 707dbc0420a3 to 23f6f5853f50 (149 revisions)

flutter/flutter@707dbc0...23f6f58

2026-05-12 737941+loic-sharma@users.noreply.github.com Add 'cp: review' label to the manual cherrypick process (flutter/flutter#186158)
2026-05-12 engine-flutter-autoroll@skia.org Roll Packages from 19ec8b861676 to 93cbed65f336 (3 revisions) (flutter/flutter#186401)
2026-05-12 30870216+gaaclarke@users.noreply.github.com Removes SDF option for macOS (always enabled) (flutter/flutter#186265)
2026-05-12 nico.reiab@gmail.com docs: fix typos in flutter_tools comments (flutter/flutter#186321)
2026-05-12 15619084+vashworth@users.noreply.github.com Pass XcodeBasedProject instead of String to functions in XcodeProjectInterpreter (flutter/flutter#186378)
2026-05-12 jason-simmons@users.noreply.github.com Update iOS scenario app test goldens to match changes from flutter/flutter#182662 (flutter/flutter#186390)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from ad0aff15b9fa to 77a21bc723dc (2 revisions) (flutter/flutter#186396)
2026-05-12 32538273+ValentinVignal@users.noreply.github.com Migrate focus_node.unfocus.0.dart to use `RadioGroup` (flutter/flutter#183979)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from 91d3c1e730af to ad0aff15b9fa (7 revisions) (flutter/flutter#186391)
2026-05-12 bdero@google.com [Flutter GPU] Allow customizing the vertex layout on a RenderPipeline (flutter/flutter#186310)
2026-05-12 97480502+b-luk@users.noreply.github.com Fix `EmbedderTest.CanRenderTextWithImpellerMetal` test breakage (flutter/flutter#186262)
2026-05-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from rFhU-YPqdCRCtCz7b... to z7ICmPtn4hspu02zk... (flutter/flutter#186384)
2026-05-12 bdero@google.com [Impeller] GLES: lazily allocate texture mip levels on first per-level write (flutter/flutter#186302)
2026-05-12 bdero@google.com [Android] Propagate --enable-flutter-gpu Intent extra to engine args (flutter/flutter#186298)
2026-05-11 47866232+chunhtai@users.noreply.github.com [ci] update no-response workflow to also look for old label name in e… (flutter/flutter#186373)
2026-05-11 bdero@google.com [ImpellerC] Write a depfile when --shader-bundle is in use (flutter/flutter#186341)
2026-05-11 nico.reiab@gmail.com docs: fix doubled-word typos in comments (flutter/flutter#186320)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 32281401997e to 91d3c1e730af (4 revisions) (flutter/flutter#186368)
2026-05-11 15619084+vashworth@users.noreply.github.com Show SwiftPM warnings right before iOS/macOS build (flutter/flutter#185984)
2026-05-11 15619084+vashworth@users.noreply.github.com Convert rebuilding-flutter-tool script to dart (flutter/flutter#185089)
2026-05-11 15619084+vashworth@users.noreply.github.com Use Xcode's LLDB (flutter/flutter#186273)
2026-05-11 mr-peipei@web.de Remove `currentMainUri` from `generateMainDartWithPluginRegistrant` (flutter/flutter#185907)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 2514f6b5f92b to 32281401997e (1 revision) (flutter/flutter#186349)
2026-05-11 engine-flutter-autoroll@skia.org Roll Packages from 92552b16bcc1 to 19ec8b861676 (4 revisions) (flutter/flutter#186350)
2026-05-11 1063596+reidbaker@users.noreply.github.com Check for absolute paths in skills.  (flutter/flutter#185632)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 9fb7d2814642 to 2514f6b5f92b (1 revision) (flutter/flutter#186347)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 8cafb209e836 to 9fb7d2814642 (4 revisions) (flutter/flutter#186335)
2026-05-10 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from sOBiPJb0xznDBZlf5... to rFhU-YPqdCRCtCz7b... (flutter/flutter#186328)
2026-05-10 engine-flutter-autoroll@skia.org Roll Skia from 05a03f99c74e to 8cafb209e836 (1 revision) (flutter/flutter#186315)
2026-05-10 bdero@google.com [Impeller] Vulkan: don't drop user-supplied viewport X, Y, and depth range (flutter/flutter#185886)
2026-05-09 mbrase@google.com Update Fuchsia tests to subpackage their child components (flutter/flutter#186259)
2026-05-09 victorsanniay@gmail.com Fix SelectableText crash with inline lambda contextMenuBuilder (flutter/flutter#184990)
2026-05-09 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from 5_TnhTsHSqtCx37o6... to sOBiPJb0xznDBZlf5... (flutter/flutter#186289)
2026-05-09 engine-flutter-autoroll@skia.org Roll Skia from dc78d4bd2efb to 05a03f99c74e (2 revisions) (flutter/flutter#186283)
2026-05-09 22373191+Hari-07@users.noreply.github.com Improve non rect platform view rendering  (flutter/flutter#182662)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 31521f8508c7 to dc78d4bd2efb (1 revision) (flutter/flutter#186278)
2026-05-08 30870216+gaaclarke@users.noreply.github.com Moves wide_gamut_macos to arm64 (flutter/flutter#186214)
2026-05-08 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)" (flutter/flutter#186266)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from a00db8749edb to 31521f8508c7 (2 revisions) (flutter/flutter#186264)
2026-05-08 97480502+b-luk@users.noreply.github.com Optimize compatible `DrawDiffRoundRect` calls to use `DrawRoundRect` (flutter/flutter#186203)
2026-05-08 bdero@google.com [triage] Add Flutter GPU as a triage team (flutter/flutter#186263)
2026-05-08 dmgr@google.com doc: Unified Check-Run User manual (flutter/flutter#186210)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 5f7adf4403d6 to a00db8749edb (1 revision) (flutter/flutter#186257)
2026-05-08 engine-flutter-autoroll@skia.org Roll Packages from cfdd1d3 to 92552b16bcc1 (1 revision) (flutter/flutter#186256)
2026-05-08 34871572+gmackall@users.noreply.github.com Add logging to figure out jvm crashes for `hot_mode_tests` (flutter/flutter#186107)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 926c09741ce2 to 5f7adf4403d6 (3 revisions) (flutter/flutter#186242)
...
creatorpiyush pushed a commit to creatorpiyush/packages that referenced this pull request Jun 10, 2026
…er#11700)

Roll Flutter from 707dbc0420a3 to 23f6f5853f50 (149 revisions)

flutter/flutter@707dbc0...23f6f58

2026-05-12 737941+loic-sharma@users.noreply.github.com Add 'cp: review' label to the manual cherrypick process (flutter/flutter#186158)
2026-05-12 engine-flutter-autoroll@skia.org Roll Packages from 19ec8b8 to 93cbed6 (3 revisions) (flutter/flutter#186401)
2026-05-12 30870216+gaaclarke@users.noreply.github.com Removes SDF option for macOS (always enabled) (flutter/flutter#186265)
2026-05-12 nico.reiab@gmail.com docs: fix typos in flutter_tools comments (flutter/flutter#186321)
2026-05-12 15619084+vashworth@users.noreply.github.com Pass XcodeBasedProject instead of String to functions in XcodeProjectInterpreter (flutter/flutter#186378)
2026-05-12 jason-simmons@users.noreply.github.com Update iOS scenario app test goldens to match changes from flutter/flutter#182662 (flutter/flutter#186390)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from ad0aff15b9fa to 77a21bc723dc (2 revisions) (flutter/flutter#186396)
2026-05-12 32538273+ValentinVignal@users.noreply.github.com Migrate focus_node.unfocus.0.dart to use `RadioGroup` (flutter/flutter#183979)
2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from 91d3c1e730af to ad0aff15b9fa (7 revisions) (flutter/flutter#186391)
2026-05-12 bdero@google.com [Flutter GPU] Allow customizing the vertex layout on a RenderPipeline (flutter/flutter#186310)
2026-05-12 97480502+b-luk@users.noreply.github.com Fix `EmbedderTest.CanRenderTextWithImpellerMetal` test breakage (flutter/flutter#186262)
2026-05-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from rFhU-YPqdCRCtCz7b... to z7ICmPtn4hspu02zk... (flutter/flutter#186384)
2026-05-12 bdero@google.com [Impeller] GLES: lazily allocate texture mip levels on first per-level write (flutter/flutter#186302)
2026-05-12 bdero@google.com [Android] Propagate --enable-flutter-gpu Intent extra to engine args (flutter/flutter#186298)
2026-05-11 47866232+chunhtai@users.noreply.github.com [ci] update no-response workflow to also look for old label name in e… (flutter/flutter#186373)
2026-05-11 bdero@google.com [ImpellerC] Write a depfile when --shader-bundle is in use (flutter/flutter#186341)
2026-05-11 nico.reiab@gmail.com docs: fix doubled-word typos in comments (flutter/flutter#186320)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 32281401997e to 91d3c1e730af (4 revisions) (flutter/flutter#186368)
2026-05-11 15619084+vashworth@users.noreply.github.com Show SwiftPM warnings right before iOS/macOS build (flutter/flutter#185984)
2026-05-11 15619084+vashworth@users.noreply.github.com Convert rebuilding-flutter-tool script to dart (flutter/flutter#185089)
2026-05-11 15619084+vashworth@users.noreply.github.com Use Xcode's LLDB (flutter/flutter#186273)
2026-05-11 mr-peipei@web.de Remove `currentMainUri` from `generateMainDartWithPluginRegistrant` (flutter/flutter#185907)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 2514f6b5f92b to 32281401997e (1 revision) (flutter/flutter#186349)
2026-05-11 engine-flutter-autoroll@skia.org Roll Packages from 92552b1 to 19ec8b8 (4 revisions) (flutter/flutter#186350)
2026-05-11 1063596+reidbaker@users.noreply.github.com Check for absolute paths in skills.  (flutter/flutter#185632)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 9fb7d2814642 to 2514f6b5f92b (1 revision) (flutter/flutter#186347)
2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 8cafb209e836 to 9fb7d2814642 (4 revisions) (flutter/flutter#186335)
2026-05-10 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from sOBiPJb0xznDBZlf5... to rFhU-YPqdCRCtCz7b... (flutter/flutter#186328)
2026-05-10 engine-flutter-autoroll@skia.org Roll Skia from 05a03f99c74e to 8cafb209e836 (1 revision) (flutter/flutter#186315)
2026-05-10 bdero@google.com [Impeller] Vulkan: don't drop user-supplied viewport X, Y, and depth range (flutter/flutter#185886)
2026-05-09 mbrase@google.com Update Fuchsia tests to subpackage their child components (flutter/flutter#186259)
2026-05-09 victorsanniay@gmail.com Fix SelectableText crash with inline lambda contextMenuBuilder (flutter/flutter#184990)
2026-05-09 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from 5_TnhTsHSqtCx37o6... to sOBiPJb0xznDBZlf5... (flutter/flutter#186289)
2026-05-09 engine-flutter-autoroll@skia.org Roll Skia from dc78d4bd2efb to 05a03f99c74e (2 revisions) (flutter/flutter#186283)
2026-05-09 22373191+Hari-07@users.noreply.github.com Improve non rect platform view rendering  (flutter/flutter#182662)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 31521f8508c7 to dc78d4bd2efb (1 revision) (flutter/flutter#186278)
2026-05-08 30870216+gaaclarke@users.noreply.github.com Moves wide_gamut_macos to arm64 (flutter/flutter#186214)
2026-05-08 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)" (flutter/flutter#186266)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from a00db8749edb to 31521f8508c7 (2 revisions) (flutter/flutter#186264)
2026-05-08 97480502+b-luk@users.noreply.github.com Optimize compatible `DrawDiffRoundRect` calls to use `DrawRoundRect` (flutter/flutter#186203)
2026-05-08 bdero@google.com [triage] Add Flutter GPU as a triage team (flutter/flutter#186263)
2026-05-08 dmgr@google.com doc: Unified Check-Run User manual (flutter/flutter#186210)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 5f7adf4403d6 to a00db8749edb (1 revision) (flutter/flutter#186257)
2026-05-08 engine-flutter-autoroll@skia.org Roll Packages from 0411f1d to 92552b1 (1 revision) (flutter/flutter#186256)
2026-05-08 34871572+gmackall@users.noreply.github.com Add logging to figure out jvm crashes for `hot_mode_tests` (flutter/flutter#186107)
2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 926c09741ce2 to 5f7adf4403d6 (3 revisions) (flutter/flutter#186242)
...
via-guy pushed a commit to via-guy/flutter that referenced this pull request Jun 26, 2026
…) (flutter#186935)

Migrates `FlutterVSyncClient` from a hybrid C++/Obj-C implementation to
a pure Objective-C implementation by removing C++ types from its
interface and implementation.

Previously, `FlutterVSyncClient` stored a C++
`flutter::VsyncWaiter::Callback` and used a temporary
`std::unique_ptr<flutter::FrameTimingsRecorder>` to propagate vsync
timestamps. This was redundant:

* `FlutterVSyncClient` allocated a temporary `FrameTimingsRecorder` and
recorded vsync times.
* It passed this to a C++ lambda wrapper.
* The lambda extracted the start/target times as seconds and passed them
to the Obj-C block callback.
* The temporary recorder was immediately discarded.
* `VsyncWaiterIOS` converted the seconds back to `fml::TimePoint`.
* `VsyncWaiter::FireCallback` allocated *another* `FrameTimingsRecorder`
and recorded the same times again.

We now:
* manage the callback as pure Obj-C block that accepts raw
`CFTimeInterval` (double seconds) directly from `CADisplayLink`.
* Remove the redundant `FrameTimingsRecorder` and C++ lambda wrapper.
* Rely solely on `VsyncWaiter::FireCallback` to handle the final
`FrameTimingsRecorder` creation and recording, which it already does.

This is a re-land of flutter#186166 which was reverted in flutter#186266. That patch
failed to correctly adjust the epoch of timestamps obtained from
CoreAnimation (which uses `mach_absolute_time` under the hood) to the
epoch used by the core engine, which is built on `fml::TimePoint`, which
uses `std::chrono::steady_clock`, which uses `mach_continuous_time`
under the hood, consistent with the C++ specification's of a continuous
clock. While these two clocks start roughly synchronized at boot,
`mach_absolute_time` pauses on device sleep, whereas
`mach_continuous_time` does not.

The iOS embedder now uses timings based on CoreAnimation throughout and
translates to `fml::TimePoint` only at the engine-embedder boundary.
This is consistent with embedders based on the embedder API, such as
macOS, which does this work in `-[FlutterEngine
viewControllerViewDidLoad]` using `FlutterTimeConverter`.

Added tests for frame rate snapping/fallback. No other test changes
because this introduces no semantic change and is covered by existing
tests recently added in: flutter#186457

Issue: flutter#112232

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