Bump skia to milestone 133 (Opus 4.6)

[mattleibow]

Summary

Update Skia from milestone 132 to 133.

Depends on: mono/skia PR (link below — must be merged first to update submodule)

🔗 mono/skia PR: mono/skia@skiasharp...dev/update-skia-m133

Changes

Submodule & Versions

• Updated externals/skia submodule to dev/update-skia-m133 branch
• Updated scripts/VERSIONS.txt: milestone 132→133, all version numbers
• Updated cgmanifest.json: commit hash, chrome_milestone, upstream_merge_commit

Regenerated Bindings

• binding/SkiaSharp/SkiaApi.generated.cs: Added fGainmap and fGainmapInfo fields to SKPngEncoderOptions struct (matching upstream SkPngEncoder::Options change)

Platform Build Configs

• Added -ljsonreader to Apple Xcode projects (macOS, iOS, tvOS) — upstream moved SkJSON to modules/jsonreader in m133
• Added jsonreader to Tizen project_def.prop link libraries

Breaking Changes Handled (m132 → m133)

Change	Risk	Action
SkJSON.h → modules/jsonreader/SkJSONReader.h	🔴	Updated include + link configs
SkPngEncoder::Options gained gainmap fields	🔴	Updated C struct + regenerated
-fstrict-aliasing extracted to GN config	🔴	Added config blocks in skia
SkMaskFilter::approximateFilteredBounds removed	🟢	Not wrapped — no action
GrContextOptions fields reordered	🟢	Field-by-field copy — no action

Testing

• ✅ Native build succeeds (macOS arm64)
• ✅ C# build succeeds (0 errors)
• ✅ 5,369 tests passed, 12 skipped (no GPU hardware), 1 flaky GC test (passes on retry)

[github-actions]

📦 Try the packages from this PR

Warning

Do not run these scripts without first reviewing the code in this PR.

Step 1 — Download the packages

bash / macOS / Linux:

curl -fsSL https://raw.githubusercontent.com/mono/SkiaSharp/main/scripts/get-skiasharp-pr.sh | bash -s -- 3659

PowerShell / Windows:

iex "& { $(irm https://raw.githubusercontent.com/mono/SkiaSharp/main/scripts/get-skiasharp-pr.ps1) } 3659"

Step 2 — Add the local NuGet source

dotnet nuget add source ~/.skiasharp/hives/pr-3659/packages --name skiasharp-pr-3659

More options

Option	Description
--successful-only / -SuccessfulOnly	Only use successful builds
--force / -Force	Overwrite previously downloaded packages
--list / -List	List available artifacts without downloading
--build-id ID / -BuildId ID	Download from a specific build

Or download manually from Azure Pipelines — look for the nuget artifact on the build for this PR.

Remove the source when you're done:

dotnet nuget remove source skiasharp-pr-3659

[github-actions]

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