[skia-sync] Merge upstream chrome/m151 bug fixes

[mattleibow]

Automated upstream bug-fix sync for m151.

Companion skia PR: mono/skia#278

[skia-sync] Merge upstream chrome/m151 bug fixes

Same-milestone (m151 → m151) bug-fix sync — bumps the externals/skia
submodule to the mono/skia PR head so we pick up the two new upstream
chrome/m151 commits (release-notes + CI-config only).

Pairs with the mono/skia PR: [skia-sync] Merge upstream chrome/m151
(head branch skia-sync/m151, target skiasharp).

Breaking change analysis

None. Upstream carried only:

• RELEASE_NOTES.md — promoted three relnotes/*.md bullets under a
  "Milestone 151" heading. These describe already-shipped m151 APIs
  (PrecompileContext::containsExternalFormat, SkPngRustEncoder::Options
fGainmap/fGainmapInfo, SkStrikeRef::getWidthsStrided) — none of
  which are exposed through our C API, so there is nothing to bind here.
• infra/bots/{jobs,tasks}.json — Skia CI try-job filtering.

No C++ headers, source files, BUILD.gn, or DEPS changed.

Version / binding updates

Because CURRENT == TARGET == 151, this is a bug-fix-only sync:

File	Change
cgmanifest.json	commitHash e1be35b25f… → 205c36a8af…; upstream_merge_commit 79e2e1538e… → 1536d39750…
externals/skia submodule	pointer bumped to 205c36a8afdb8504a6bdaa602996b44a6b1bcc70 (the mono/skia merge commit on skia-sync/m151)

Not touched (as expected for a same-milestone sync):

• scripts/VERSIONS.txt (milestone/soname/nuget versions unchanged)
• scripts/azure-templates-variables.yml (SKIASHARP_VERSION unchanged)
• externals/skia/include/c/sk_types.h (SK_C_INCREMENT still 0)
• binding/SkiaSharp/SkiaApi.generated.cs (regenerated → identical output)
• Any *.generated.cs, binding/**/*.cs, or documentation/**

The Phase 6 script (update-versions.ps1 -Current 151 -Target 151 -UpstreamRef chrome/m151) exited with ✅ GATE PASSED — same-milestone sync, version numbers unchanged.

C# changes

None. Phase 8's regenerate step reported:

--- Binding diff summary ---
  No changes to bindings (C API signatures unchanged)

--- New generated functions (may need C# wrappers) ---
  No new functions found

Phase 9 is therefore a no-op — no wrappers needed.

Build / test results (Linux x64)

Phase	Command	Result
7	dotnet cake --target=externals-linux --arch=x64	✅ 15m 27s, libSkiaSharp.so.151.0.0 + libHarfBuzzSharp.so.0.61421.0 produced
8	pwsh .agents/skills/update-skia/scripts/regenerate-bindings.ps1	✅ No binding diff
10 (C# build)	dotnet build binding/SkiaSharp/SkiaSharp.csproj	✅ 0 warnings, 0 errors
10 (tests)	dotnet test tests/SkiaSharp.Tests.Console/SkiaSharp.Tests.Console.csproj	✅ Passed 5584, Failed 0, Skipped 172 (2m 38s, net10.0|x64)

Full test log is uploaded as the test-output.txt workflow artifact.
Only Linux x64 was built here (workflow constraint); other platforms
(Windows/macOS/iOS/Android/WASM) will be exercised by CI on the PR.

Items needing human attention

None. The sync is limited to metadata; there are no risky surface changes
and every gate passed on the first attempt.

Created by skia-upstream-sync.

[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 -- 4312

PowerShell / Windows:

iex "& { $(irm https://raw.githubusercontent.com/mono/SkiaSharp/main/scripts/get-skiasharp-pr.ps1) } 4312"

Step 2 — Add the local NuGet source

dotnet nuget add source ~/.skiasharp/hives/pr-4312/packages --name skiasharp-pr-4312

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-4312

[github-actions]

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