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iOS: Remove the synchronous first-frame wait - #190432
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-waitForFirstFrameSync: is a no-op on iOS. The iOS embedder now only supports merged platform/UI thread task runners on the iOS main thread. `FlutterDartProject.mm` passes `require_merged_platform_ui_thread` to `SettingsFromCommandLine`, and flutter#190051 prevents the `mergeAfterLaunch` configuration (which was never implemented for iOS. Because of this, the thread calling this method at first layout is the thread responsible for producing the frame, and `Shell::WaitForFirstFrame` always ends up taking the `kFailedPrecondition` bailout without waiting. This removes the method and its only call site in FlutterViewController's first layout. This *was* the main-thread wait introduced in flutter-team-archive/engine#9506 to avoid presenting a black first frame when transitioning into a FlutterViewController with a prewarmed engine (flutter#32937). It has been dead code since the platform and UI threads merged. Maybe more intuitive evidence of this is that the main thread can't block waiting for a frame that it itself has to produce. Because I'm paranoid, I tested locally on a physical device (since the original issue mentioned this doesn't repro on simulators) on both debug and release builds using https://github.com/cbracken/flutter_flashofblack just to be 100% sure this didn't sneak back in at some point during or after the thread merge. It still looks good to me. No test changes: the wait and its call site had no coverage, and regardless the removed code has been dead code for a couple years.
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…12406) Manual roll Flutter from e52f01c920ad to b766512c65d8 (42 revisions) Manual roll requested by [email protected] flutter/flutter@e52f01c...b766512 2026-08-04 [email protected] Roll Dart SDK from 2a799a2404e9 to 9859c0a39adb (4 revisions) (flutter/flutter#190521) 2026-08-04 [email protected] Revert: iOS: Eliminate use of IOSContextNoop in platform view tests (flutter/flutter#190501) 2026-08-04 [email protected] [Impeller] Enable ETC2/ASTC LDR/BC texture compression features at Vulkan device creation (flutter/flutter#189303) 2026-08-03 [email protected] Remove openglessdf from impeller_unittests. (flutter/flutter#190469) 2026-08-03 [email protected] [web] Unify image decoding and codecs on CanvasKit and Skwasm (flutter/flutter#188573) 2026-08-03 [email protected] iOS: Eliminate use of IOSContextNoop in platform view tests (flutter/flutter#190419) 2026-08-03 [email protected] Add path rendering benchmarks (flutter/flutter#188654) 2026-08-03 [email protected] Add windows platform support for primitive_shape_test integration test (flutter/flutter#190464) 2026-08-03 [email protected] Roll Skia from 958c1c1921a1 to a08d918ebd6a (3 revisions) (flutter/flutter#190467) 2026-08-03 [email protected] tests: add --ios-runtime param (flutter/flutter#190414) 2026-08-03 [email protected] iOS: Remove the synchronous first-frame wait (flutter/flutter#190432) 2026-08-03 [email protected] iOS: Eliminate the Impeller/Skia backend selection params (flutter/flutter#190416) 2026-08-03 [email protected] iOS,macOS: Use @autoclosure in Logger (flutter/flutter#190417) 2026-08-03 [email protected] tools: Support FLUTTER_HOST_ARCH in update_dart_sdk scripts (flutter/flutter#190421) 2026-08-03 [email protected] iOS: Hardcode rendering API to Metal in tests (no-op) (flutter/flutter#190422) 2026-08-03 [email protected] a11y: Map disabled/read-only semantics to AX node restriction (flutter/flutter#190353) 2026-08-03 [email protected] [Infra] Replace defunct umbrella template with Wasm issue form (flutter/flutter#190471) 2026-08-03 [email protected] Roll Skia from abecb0dc02c1 to 958c1c1921a1 (4 revisions) (flutter/flutter#190459) 2026-08-03 [email protected] Roll Dart SDK from 65b163be2485 to 2a799a2404e9 (3 revisions) (flutter/flutter#190454) 2026-08-03 [email protected] Roll Skia from 68efb3f2ad16 to abecb0dc02c1 (1 revision) (flutter/flutter#190443) 2026-08-03 [email protected] Roll Packages from 5351d8c to ac87e65 (4 revisions) (flutter/flutter#190441) 2026-08-03 [email protected] Roll Skia from 5a761eb826c1 to 68efb3f2ad16 (1 revision) (flutter/flutter#190440) 2026-08-03 [email protected] Roll Skia from 4c9f8b4805e2 to 5a761eb826c1 (1 revision) (flutter/flutter#190437) 2026-08-03 [email protected] [macOS] Resume app lifecycle on becomeActive to avoid frozen UI after occlusion (flutter/flutter#188772) 2026-08-03 [email protected] Roll Skia from 39cda9d6d7d2 to 4c9f8b4805e2 (6 revisions) (flutter/flutter#190426) 2026-08-03 [email protected] Roll Skia from df13bfb5a54e to 39cda9d6d7d2 (2 revisions) (flutter/flutter#190425) 2026-08-02 [email protected] iOS: Serialise CADisplayLink access in VSyncClient tests (flutter/flutter#190335) 2026-08-02 [email protected] Roll Skia from 32329e5643b5 to df13bfb5a54e (1 revision) (flutter/flutter#190394) 2026-08-02 [email protected] [Impeller] Skip binding dead-code-eliminated resources on Metal (flutter/flutter#190040) 2026-08-01 [email protected] [Flutter GPU] Raise Dart errors for invalid render pipelines and memoize per-draw pipeline state (flutter/flutter#189899) 2026-08-01 [email protected] Revert "Improve non rect platform view rendering (#182662)" (flutter/flutter#190003) 2026-08-01 [email protected] Roll Skia from ebf50520d720 to 32329e5643b5 (1 revision) (flutter/flutter#190389) 2026-08-01 [email protected] Roll Skia from f73c4510d12d to ebf50520d720 (6 revisions) (flutter/flutter#190376) 2026-07-31 [email protected] Primitive shape integration test (flutter/flutter#190368) 2026-07-31 [email protected] Eliminate some early returns in uber_sdf.frag to fix broken UberSDF AA on Windows (flutter/flutter#190260) 2026-07-31 [email protected] chore: swiftshader mirrored + llvm16 (flutter/flutter#181225) 2026-07-31 [email protected] [web] Remove in-repo agent documentation (flutter/flutter#190326) 2026-07-31 [email protected] [windows]: Uses offscreen MSAA when implicit msaa isn't available. (flutter/flutter#190256) 2026-07-31 [email protected] flutter_tools: Use new FileSystemExtension from devtools (flutter/flutter#190360) 2026-07-31 [email protected] Roll Dart SDK from c3acfc2479f6 to 65b163be2485 (1 revision) (flutter/flutter#190358) 2026-07-31 [email protected] Use devicectl for screenshots on Xcode 27, remove idevicescreenshot artifact (flutter/flutter#189091) 2026-07-31 [email protected] Roll Skia from 7ef86a5b0eb9 to f73c4510d12d (1 revision) (flutter/flutter#190352) If this roll has caused a breakage, revert this CL and stop the roller ...
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-waitForFirstFrameSync:is a no-op on iOS. The iOS embedder now only supports merged platform/UI thread task runners on the iOS main thread.FlutterDartProject.mmpassesrequire_merged_platform_ui_threadtoSettingsFromCommandLine, and #190051 prevents themergeAfterLaunchconfiguration (which was never implemented for iOS. Because of this, the thread calling this method at first layout is the thread responsible for producing the frame, andShell::WaitForFirstFramealways ends up taking thekFailedPreconditionbailout without waiting.This removes the method and its only call site in FlutterViewController's first layout.
This was the main-thread wait introduced in flutter-team-archive/engine#9506 to avoid presenting a black first frame when transitioning into a FlutterViewController with a prewarmed engine (#32937).
It has been dead code since the platform and UI threads merged. Maybe more intuitive evidence of this is that the main thread can't block waiting for a frame that it itself has to produce.
Because I'm paranoid, I tested locally on a physical device (since the original issue mentioned this doesn't repro on simulators) on both debug and release builds using https://github.com/cbracken/flutter_flashofblack just to be 100% sure this didn't sneak back in at some point during or after the thread merge. It still looks good to me.
No test changes: the wait and its call site had no coverage, and regardless the removed code has been dead code for a couple years.
Issue: #112232 (prework)
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