Add WindowSize property to BrotliCompressionOptions

[iremyux]

This PR adds a WindowSize property to BrotliCompressionOptions to allow developers to configure the Brotli compression window size (valid range: 10-24, default: 22). The window size controls the maximum distance for back-references in the LZ77 algorithm, where larger windows can improve compression for data with long-distance repetitions. Includes corresponding validation tests following the existing pattern established for the Quality property.

Fixes #116227

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-io-compression
See info in area-owners.md if you want to be subscribed.

[Copilot]

Pull Request Overview

This PR adds a WindowSize property to the BrotliCompressionOptions class, allowing developers to configure the Brotli compression window size. The window size controls the sliding window size in bits for the LZ77 algorithm, with valid values ranging from 10 to 24 and a default of 22.

• Added WindowSize property to BrotliCompressionOptions with validation (10-24 range)
• Integrated window size configuration into BrotliStream compression constructor
• Added comprehensive test coverage for window size validation

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/enc/BrotliCompressionOptions.cs	Added WindowSize property with validation using BrotliUtils constants
src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/enc/BrotliStream.Compress.cs	Applied window size configuration to encoder when using compression options
src/libraries/System.IO.Compression.Brotli/ref/System.IO.Compression.Brotli.cs	Updated public API reference to include WindowSize property
src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs	Added test to validate window size property including default value and boundary conditions

Comments suppressed due to low confidence (1)

src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/enc/BrotliCompressionOptions.cs:27

• The Quality property validation uses hardcoded literals (0, 11) instead of BrotliUtils constants, unlike the WindowSize property which uses BrotliUtils.WindowBits_Min and BrotliUtils.WindowBits_Max. For consistency and maintainability, consider using BrotliUtils.Quality_Min and BrotliUtils.Quality_Max here as well.

                ArgumentOutOfRangeException.ThrowIfLessThan(value, 0, nameof(value));
                ArgumentOutOfRangeException.ThrowIfGreaterThan(value, 11, nameof(value));

[rzikm]

@bartonjs I just realized, the Zstandard proposal named similar property Window, and the existing ctor parameter on BrotliEncoder is also called window. I think we should make sure the names are consistent.

Unfortunately, we are already somewhat inconsistent because DeflateStream parameters are called windowBits, but we'd better not add a third name for the same thing.

[bartonjs]

Sounds like Window is the more naturally aligned name, so it's probably fine to go ahead and use it. Send a blurb to FXDC to see if anyone wants to object.