)]}'
{
  "commit": "291001ef1e907da5c01453cb0d5fcb30b3a96260",
  "tree": "a441bb6adbbb4e124ad0f966f333e317ab33488e",
  "parents": [
    "e5c4fbab25957efc624ef2cdf01b5392570df7f6"
  ],
  "author": {
    "name": "Chris Bracken",
    "email": "chris@bracken.jp",
    "time": "Fri May 08 08:33:11 2026 +0900"
  },
  "committer": {
    "name": "GitHub",
    "email": "noreply@github.com",
    "time": "Thu May 07 23:33:11 2026 +0000"
  },
  "message": "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)\n\nMigrates `FlutterVSyncClient` from a hybrid C++/Obj-C implementation to\na pure Objective-C implementation by removing C++ types from its\ninterface and implementation.\n\nPreviously, `FlutterVSyncClient` stored a C++\n`flutter::VsyncWaiter::Callback` and used a temporary\n`std::unique_ptr\u003cflutter::FrameTimingsRecorder\u003e` to propagate vsync\ntimestamps. This was redundant:\n\n* `FlutterVSyncClient` allocated a temporary `FrameTimingsRecorder` and\nrecorded vsync times.\n* It passed this to a C++ lambda wrapper.\n* The lambda extracted the start/target times as seconds and passed them\nto the Obj-C block callback.\n* The temporary recorder was immediately discarded.\n* `VsyncWaiterIOS` converted the seconds back to `fml::TimePoint`.\n* `VsyncWaiter::FireCallback` allocated *another* `FrameTimingsRecorder`\nand recorded the same times again.\n\nWe now:\n* manage the callback as pure Obj-C block that accepts raw\n`CFTimeInterval` (double seconds) directly from `CADisplayLink`.\n* Remove the redundant `FrameTimingsRecorder` and C++ lambda wrapper.\n* Rely solely on `VsyncWaiter::FireCallback` to handle the final\n`FrameTimingsRecorder` creation and recording, which it already does.\n\nNo test changes because this introduces no semantic change and is\ncovered by existing tests recently added in:\n\nhttps://github.com/flutter/flutter/blob/master/engine/src/flutter/shell/platform/darwin/ios/framework/Source/VSyncClientTest.swift\n\n## Pre-launch Checklist\n\n- [X] I read the [Contributor Guide] and followed the process outlined\nthere for submitting PRs.\n- [X] I read the [AI contribution guidelines] and understand my\nresponsibilities, or I am not using AI tools.\n- [X] I read the [Tree Hygiene] wiki page, which explains my\nresponsibilities.\n- [X] I read and followed the [Flutter Style Guide], including [Features\nwe expect every widget to implement].\n- [X] I signed the [CLA].\n- [X] I listed at least one issue that this PR fixes in the description\nabove.\n- [X] I updated/added relevant documentation (doc comments with `///`).\n- [X] I added new tests to check the change I am making, or this PR is\n[test-exempt].\n- [X] I followed the [breaking change policy] and added [Data Driven\nFixes] where supported.\n- [X] All existing and new tests are passing.\n\nIf you need help, consider asking for advice on the #hackers-new channel\non [Discord].\n\nIf this change needs to override an active code freeze, provide a\ncomment explaining why. The code freeze workflow can be overridden by\ncode reviewers. See pinned issues for any active code freezes with\nguidance.\n\n**Note**: The Flutter team is currently trialing the use of [Gemini Code\nAssist for\nGitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code).\nComments from the `gemini-code-assist` bot should not be taken as\nauthoritative feedback from the Flutter team. If you find its comments\nuseful you can update your code accordingly, but if you are unsure or\ndisagree with the feedback, please feel free to wait for a Flutter team\nmember\u0027s review for guidance on which automated comments should be\naddressed.\n\n\u003c!-- Links --\u003e\n[Contributor Guide]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview\n[AI contribution guidelines]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines\n[Tree Hygiene]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md\n[test-exempt]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests\n[Flutter Style Guide]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md\n[Features we expect every widget to implement]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement\n[CLA]: https://cla.developers.google.com/\n[flutter/tests]: https://github.com/flutter/tests\n[breaking change policy]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes\n[Discord]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md\n[Data Driven Fixes]:\nhttps://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "57c744ce43e82798ea3bb705673212da2cee11d7",
      "old_mode": 33188,
      "old_path": "engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterVSyncClient.mm",
      "new_id": "b484855da7fbf87601bbd703c364ba43bcf2f190",
      "new_mode": 33188,
      "new_path": "engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterVSyncClient.mm"
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}