[wimp] Initial Impeller on Web implementation. - #175442

…er#175442)

…er#175442)

…er#175442)

…er#175442)

This PR adds an initial implementation of a impeller-based version of
skwasm. As of right now, the main things that are missing are:
* Image support flutter#175371
* Custom shader support flutter#175431
* Turn on MSAA flutter#175441
* Multithreading is turned off
flutter#178749

I plan on implementing these in smaller followup PRs.

Towards flutter#174980

…er#175442)

Manual roll Flutter from 6a1f5b7 to e25d71b (30 revisions)

Manual roll requested by [email protected]

flutter/flutter@6a1f5b7...e25d71b

2025-12-10 [email protected] Ensure that the engine converts std::filesystem::path objects to UTF-8 strings on Windows (flutter/flutter#179528)
2025-12-10 [email protected] Fix the issue with pinned headers in nested SliverMainAxisGroup. (flutter/flutter#179132)
2025-12-10 [email protected] added onUserInteractionIfError for form (flutter/flutter#175515)
2025-12-10 [email protected] Fixed RenderFlex overflow in RouteObserver Example (flutter/flutter#170980)
2025-12-10 [email protected] Roll Dart SDK from 17749965ec57 to 077062c5e515 (3 revisions) (flutter/flutter#179691)
2025-12-10 [email protected] Manually roll characters (flutter/flutter#179447)
2025-12-10 [email protected] Roll Packages from 338ecd3 to 74a5a53 (4 revisions) (flutter/flutter#179693)
2025-12-10 [email protected] Marks Mac_ios draw_arcs_all_stroke_styles_perf_ios__timeline_summary to be unflaky (flutter/flutter#179669)
2025-12-10 [email protected] Check for a null cached image in SingleFrameCodec::getNextFrame (flutter/flutter#179483)
2025-12-10 [email protected] Roll Fuchsia Linux SDK from _pSztGZvEA3-Ry-GW... to u5vxWTRT0HlxOP5_r... (flutter/flutter#179652)
2025-12-10 [email protected] Implement flutter/accessibility channel (flutter/flutter#179484)
2025-12-10 [email protected] Roll Skia from 82fff05cc621 to e61cc6d073fd (4 revisions) (flutter/flutter#179646)
2025-12-10 [email protected] Make sure that a CupertinoDialogAction doesn't crash in 0x0 environment (flutter/flutter#178956)
2025-12-10 [email protected] Make SettingsChannel configuration queue not static (flutter/flutter#179636)
2025-12-10 [email protected] Make sure that a CupertinoListSection doesn't crash in 0x0 environment (flutter/flutter#179068)
2025-12-10 [email protected] Make sure that a CupertinoFormSection doesn't crash in 0x0 environment (flutter/flutter#179001)
2025-12-10 [email protected] Make sure that a CupertinoMagnifier doesn't crash in 0x0 environment (flutter/flutter#179206)
2025-12-10 [email protected] Make sure that a Tooltip doesn't crash in 0x0 environment (flutter/flutter#178461)
2025-12-10 [email protected] Make sure that a CupertinoSegmentedControl doesn't crash in 0x0 envir… (flutter/flutter#179544)
2025-12-10 [email protected] Make sure that a CupertinoSlider doesn't crash in 0x0 environment (flutter/flutter#179566)
2025-12-10 [email protected] Make sure that a CupertinoPageScaffold doesn't crash in 0x0 environment (flutter/flutter#179245)
2025-12-09 [email protected] Roll Skia from f9e32c28c5c5 to 82fff05cc621 (2 revisions) (flutter/flutter#179641)
2025-12-09 [email protected] Roll Dart SDK from 019cb923bf62 to 17749965ec57 (5 revisions) (flutter/flutter#179640)
2025-12-09 [email protected] Enhance documentation for `LocalHistoryEntry` class (flutter/flutter#179223)
2025-12-09 [email protected] WebParagrah: ellipsis (flutter/flutter#178748)
2025-12-09 [email protected] Update the doc on Google Testing to reflect the current state (flutter/flutter#177187)
2025-12-09 [email protected] [wimp] Initial Impeller on Web implementation. (flutter/flutter#175442)
2025-12-09 [email protected] Relax assertion for adding semantics locale (flutter/flutter#178140)
2025-12-09 [email protected] Fix Scrollbar drag behavior (flutter/flutter#179199)
2025-12-09 [email protected] Roll Skia from 502ee6f2a0d7 to f9e32c28c5c5 (6 revisions) (flutter/flutter#179632)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-packages
Please CC [email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
...

…0601)

Manual roll Flutter from 6a1f5b7 to e25d71b (30 revisions)

Manual roll requested by [email protected]

flutter/flutter@6a1f5b7...e25d71b

2025-12-10 [email protected] Ensure that the engine converts std::filesystem::path objects to UTF-8 strings on Windows (flutter/flutter#179528)
2025-12-10 [email protected] Fix the issue with pinned headers in nested SliverMainAxisGroup. (flutter/flutter#179132)
2025-12-10 [email protected] added onUserInteractionIfError for form (flutter/flutter#175515)
2025-12-10 [email protected] Fixed RenderFlex overflow in RouteObserver Example (flutter/flutter#170980)
2025-12-10 [email protected] Roll Dart SDK from 17749965ec57 to 077062c5e515 (3 revisions) (flutter/flutter#179691)
2025-12-10 [email protected] Manually roll characters (flutter/flutter#179447)
2025-12-10 [email protected] Roll Packages from 338ecd3 to 74a5a53 (4 revisions) (flutter/flutter#179693)
2025-12-10 [email protected] Marks Mac_ios draw_arcs_all_stroke_styles_perf_ios__timeline_summary to be unflaky (flutter/flutter#179669)
2025-12-10 [email protected] Check for a null cached image in SingleFrameCodec::getNextFrame (flutter/flutter#179483)
2025-12-10 [email protected] Roll Fuchsia Linux SDK from _pSztGZvEA3-Ry-GW... to u5vxWTRT0HlxOP5_r... (flutter/flutter#179652)
2025-12-10 [email protected] Implement flutter/accessibility channel (flutter/flutter#179484)
2025-12-10 [email protected] Roll Skia from 82fff05cc621 to e61cc6d073fd (4 revisions) (flutter/flutter#179646)
2025-12-10 [email protected] Make sure that a CupertinoDialogAction doesn't crash in 0x0 environment (flutter/flutter#178956)
2025-12-10 [email protected] Make SettingsChannel configuration queue not static (flutter/flutter#179636)
2025-12-10 [email protected] Make sure that a CupertinoListSection doesn't crash in 0x0 environment (flutter/flutter#179068)
2025-12-10 [email protected] Make sure that a CupertinoFormSection doesn't crash in 0x0 environment (flutter/flutter#179001)
2025-12-10 [email protected] Make sure that a CupertinoMagnifier doesn't crash in 0x0 environment (flutter/flutter#179206)
2025-12-10 [email protected] Make sure that a Tooltip doesn't crash in 0x0 environment (flutter/flutter#178461)
2025-12-10 [email protected] Make sure that a CupertinoSegmentedControl doesn't crash in 0x0 envir… (flutter/flutter#179544)
2025-12-10 [email protected] Make sure that a CupertinoSlider doesn't crash in 0x0 environment (flutter/flutter#179566)
2025-12-10 [email protected] Make sure that a CupertinoPageScaffold doesn't crash in 0x0 environment (flutter/flutter#179245)
2025-12-09 [email protected] Roll Skia from f9e32c28c5c5 to 82fff05cc621 (2 revisions) (flutter/flutter#179641)
2025-12-09 [email protected] Roll Dart SDK from 019cb923bf62 to 17749965ec57 (5 revisions) (flutter/flutter#179640)
2025-12-09 [email protected] Enhance documentation for `LocalHistoryEntry` class (flutter/flutter#179223)
2025-12-09 [email protected] WebParagrah: ellipsis (flutter/flutter#178748)
2025-12-09 [email protected] Update the doc on Google Testing to reflect the current state (flutter/flutter#177187)
2025-12-09 [email protected] [wimp] Initial Impeller on Web implementation. (flutter/flutter#175442)
2025-12-09 [email protected] Relax assertion for adding semantics locale (flutter/flutter#178140)
2025-12-09 [email protected] Fix Scrollbar drag behavior (flutter/flutter#179199)
2025-12-09 [email protected] Roll Skia from 502ee6f2a0d7 to f9e32c28c5c5 (6 revisions) (flutter/flutter#179632)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-packages
Please CC [email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
...

…er#175442)

…0601)

Manual roll Flutter from 6a1f5b7 to e25d71b (30 revisions)

Manual roll requested by [email protected]

flutter/flutter@6a1f5b7...e25d71b

2025-12-10 [email protected] Ensure that the engine converts std::filesystem::path objects to UTF-8 strings on Windows (flutter/flutter#179528)
2025-12-10 [email protected] Fix the issue with pinned headers in nested SliverMainAxisGroup. (flutter/flutter#179132)
2025-12-10 [email protected] added onUserInteractionIfError for form (flutter/flutter#175515)
2025-12-10 [email protected] Fixed RenderFlex overflow in RouteObserver Example (flutter/flutter#170980)
2025-12-10 [email protected] Roll Dart SDK from 17749965ec57 to 077062c5e515 (3 revisions) (flutter/flutter#179691)
2025-12-10 [email protected] Manually roll characters (flutter/flutter#179447)
2025-12-10 [email protected] Roll Packages from 338ecd3 to 74a5a53 (4 revisions) (flutter/flutter#179693)
2025-12-10 [email protected] Marks Mac_ios draw_arcs_all_stroke_styles_perf_ios__timeline_summary to be unflaky (flutter/flutter#179669)
2025-12-10 [email protected] Check for a null cached image in SingleFrameCodec::getNextFrame (flutter/flutter#179483)
2025-12-10 [email protected] Roll Fuchsia Linux SDK from _pSztGZvEA3-Ry-GW... to u5vxWTRT0HlxOP5_r... (flutter/flutter#179652)
2025-12-10 [email protected] Implement flutter/accessibility channel (flutter/flutter#179484)
2025-12-10 [email protected] Roll Skia from 82fff05cc621 to e61cc6d073fd (4 revisions) (flutter/flutter#179646)
2025-12-10 [email protected] Make sure that a CupertinoDialogAction doesn't crash in 0x0 environment (flutter/flutter#178956)
2025-12-10 [email protected] Make SettingsChannel configuration queue not static (flutter/flutter#179636)
2025-12-10 [email protected] Make sure that a CupertinoListSection doesn't crash in 0x0 environment (flutter/flutter#179068)
2025-12-10 [email protected] Make sure that a CupertinoFormSection doesn't crash in 0x0 environment (flutter/flutter#179001)
2025-12-10 [email protected] Make sure that a CupertinoMagnifier doesn't crash in 0x0 environment (flutter/flutter#179206)
2025-12-10 [email protected] Make sure that a Tooltip doesn't crash in 0x0 environment (flutter/flutter#178461)
2025-12-10 [email protected] Make sure that a CupertinoSegmentedControl doesn't crash in 0x0 envir… (flutter/flutter#179544)
2025-12-10 [email protected] Make sure that a CupertinoSlider doesn't crash in 0x0 environment (flutter/flutter#179566)
2025-12-10 [email protected] Make sure that a CupertinoPageScaffold doesn't crash in 0x0 environment (flutter/flutter#179245)
2025-12-09 [email protected] Roll Skia from f9e32c28c5c5 to 82fff05cc621 (2 revisions) (flutter/flutter#179641)
2025-12-09 [email protected] Roll Dart SDK from 019cb923bf62 to 17749965ec57 (5 revisions) (flutter/flutter#179640)
2025-12-09 [email protected] Enhance documentation for `LocalHistoryEntry` class (flutter/flutter#179223)
2025-12-09 [email protected] WebParagrah: ellipsis (flutter/flutter#178748)
2025-12-09 [email protected] Update the doc on Google Testing to reflect the current state (flutter/flutter#177187)
2025-12-09 [email protected] [wimp] Initial Impeller on Web implementation. (flutter/flutter#175442)
2025-12-09 [email protected] Relax assertion for adding semantics locale (flutter/flutter#178140)
2025-12-09 [email protected] Fix Scrollbar drag behavior (flutter/flutter#179199)
2025-12-09 [email protected] Roll Skia from 502ee6f2a0d7 to f9e32c28c5c5 (6 revisions) (flutter/flutter#179632)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-packages
Please CC [email protected],[email protected] on the revert to ensure that a human
is aware of the problem.

To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
...

…ders (flutter#192238)

This PR fixes macOS web engine builds in `local_engine.json` by
addressing two requirements:

1. **Xcode dependency**: With the addition of Wimp (Impeller on Web) to
`flutter_web_sdk_archive` in flutter#175442, wasm builds now pull in Impeller,
which compiles host utilities (`impellerc` and `flatc`). On macOS hosts,
`compiled_action` evaluates the macOS host toolchain which requires the
Darwin SDK / Xcode. When `skip_xcode_install: true` was added in
flutter#162164, Web SDK only compiled Skia and Skwasm targets via Emscripten
without host tools. Re-adds `"sdk_version": "17c52"` to
`macos/wasm_release` and `macos/wasm_debug_unopt`.

2. **OpenJDK dependency**: On Apple Silicon (`arm64`) macOS bots without
Rosetta 2, Emscripten's `google-closure-compiler` fails when attempting
to spawn its native x86_64 binary (`EBADARCH`, `errno: -86`). It falls
back to its Java implementation, which requires a JDK on `$PATH`. Adds
OpenJDK 21 to `properties.dependencies` so `flutter_deps` installs the
native `mac-arm64` OpenJDK and prepends it to `$PATH`.

Fixes flutter#180648

## 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].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant in-code documentation (doc comments with
`///`).
- [ ] If this PR introduces a new feature or capability, I created and
linked a website documentation issue or PR in [flutter/website] (or
verified none is needed).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[AI contribution guidelines]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[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/
[flutter/tests]: https://github.com/flutter/tests
[flutter/website]: https://github.com/flutter/website
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

…nt inner skip

- Dispose `Paragraph` and `Picture` inside `drawText` and register `addTearDown(image.dispose)`.
- Remove the redundant inner `skip: isSafari || isFirefox` on `Renders tab as space instead of tofu` (already applied on the enclosing `group('Text', ..., skip: isSafari || isFirefox)`).
- Correct historical commit attribution in PR notes (flutter#175442 introduced `DlWimpImageFromPicture::GetImpellerTexture` with a null `TypographerContext`, flutter#183913 added the `!isWimp` skip, and flutter#191747 refactored `GetImpellerTexture` to use `ImpellerRenderContext`).

…193426)

Unskips `Renders tab as space instead of tofu` in
`engine/src/flutter/lib/web_ui/test/ui/text_test.dart` on Wimp
(`chrome-dart2wasm-wimp-ui`) and strengthens the test assertions:

- When `DlWimpImageFromPicture::GetImpellerTexture` was introduced in
flutter#175442 (`e0f544bf620`), it
constructed a temporary `impeller::AiksContext` with a `nullptr`
`TypographerContext`, causing `picture.toImage()` to drop text runs and
return blank images (which caused `matchImage(tabImage, tofuImage)` to
fail when the `!isWimp` skip was added in
flutter#183913 / `2490c22d5be`).
- flutter#191747 (`87c02198123`)
refactored `DlWimpImageFromPicture::GetImpellerTexture` to render via
`ImpellerRenderContext` (which owns the shared
`impeller::ContentContext` and `TypographerContextSkia::Make()`),
restoring `.notdef` glyph rendering in `picture.toImage()`.
- Removes the `!isWimp` guard so `Renders tab as space instead of tofu`
runs on both Skwasm and Wimp.
- Adds an assertion that unassigned non-control codepoints (`\u{0378}`)
also render a `.notdef` tofu box distinct from `''`, and disposes
`Paragraph`, `Picture`, and `Image` resources created inside `drawText`.

Fixes flutter#183944

## 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].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant in-code documentation (doc comments with
`///`).
- [x] If this PR introduces a new feature or capability, I created and
linked a website documentation issue or PR in [flutter/website] (or
verified none is needed).
- [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.

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[AI contribution guidelines]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[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/
[flutter/tests]: https://github.com/flutter/tests
[flutter/website]: https://github.com/flutter/website
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md