Chromium Work in 2025

A technical index of browser, PDF, tooling, and image-codec work from the year.

Areas of Work

Tab Focus - Command-line tab matching, focus behavior, and result output for automation.
JPEG XL - Chromium integration, SIMD paths, HDR support, and decoder APIs developed with the jxl-rs community.
Omarchy Chromium - Downstream Chromium builds used by Omarchy, including ARM64 Linux packages.

Resource Timing Across Browser Engines

Resource Timing Level 3 interim-response timestamps for HTTP 103 Early Hints required corresponding changes in each browser engine:

Browser	Status	Link
Chromium	✅ Merged	crrev.com/c/6900896
Firefox	✅ Landed	D276668
Safari/WebKit	✅ Merged	#55467

Thank You

Yoav Weiss - for patient guidance, answering questions, finding the right reviewers, and pointing me to the relevant mailing lists
@tobi - for the original idea that became the --focus flag
DHH - for Omarchy and pushing browser theming forward
Rick Byers - for championing JPEG XL's return and providing direction
Philip Jägenstedt - for supporting the JPEG XL revival effort

Thanks also to the Chromium developers who answered questions and provided feedback on Slack and in code review.

Selected Topics

Feature	Description
Tab Focus Flag (Chrome 143)	New `--focus` flag that focuses existing tabs instead of opening duplicates
Instant Policy Refresh	Added `--refresh-platform-policy` flag for instant browser theme updates via managed policies
Wayland Crash Fix	Fixed a crash affecting Linux users when moving Chrome windows between monitors
JPEG XL Support (Targeting Chrome 155)	Rust-based jxl-rs decoder, approved through the Intent to Ship process

Chromium Bug Fixes

MERGED Fix use-after-free in OmniboxEditModel
MERGED Fix styleSheets access for DOMParser-created documents
MERGED Fix HTTP 425 retry for TLS early data
MERGED Fix Cache-Control parsing (RFC 7234)
MERGED Fix iframe unload events during document.open()
MERGED Fix modulepreload referrer headers
MERGED Fix filter:invert on high-DPI displays

Other Chromium Features

MERGED Expose Font Service for font enumeration
MERGED PDFium v2 font matching feature flag
MERGED Separate defer/module script execution
MERGED ReportBody.toJSON() use counters

DevTools

PDFium

PDFium work in 2025:

New APIs:

MERGED Add FPDF_SYSFONTINFO v2 for per-request font matching
MERGED Add FPDFPage_InsertObjectAtIndex() API
MERGED Add FPDFFormObj_RemoveObject API
MERGED Add FPDFAnnot_SetFormFieldFlags API
MERGED Add API to retrieve MIME type from attachments
MERGED Implement PDF version handling from catalog

Bug Fixes:

MERGED Fix GetLooseBounds char box containment
MERGED Fix Form XObject content regeneration
MERGED Fix undo counting for cut operations

jxl-rs

Upstream work in libjxl/jxl-rs, the Rust JPEG XL decoder:

SIMD Optimizations:

MERGED Add SIMD table lookup with shuffle
MERGED Add SIMD F32 to U8/U16 conversions
MERGED Add SIMD versions of transfer functions
MERGED Add SIMD upsampling for 2x, 4x, and 8x
MERGED Add min and store_interleaved functions to jxl_simd
MERGED Add SIMD noise convolution
MERGED Add SIMD chroma upsampling
MERGED Add SIMD YCbCr to RGB conversion

Performance:

MERGED Add SinglePropertyLookup for table-based routing
MERGED Optimize EPF sigma for modular encoding
MERGED Cache default quantization tables using OnceLock
MERGED Implement flattened modular trees
MERGED Improve weighted predictor cache locality
MERGED Cache natural coefficient orders using OnceLock
MERGED Precompute cosines in spline rendering

API & Integration:

MERGED Add premultiply_output option
MERGED Add FFI-friendly API for Chromium integration
MERGED Implement remaining decoder API methods
MERGED Add preview frame API support

Bug Fixes:

MERGED Fix rendering bugs introduced in PR #577
MERGED Fix spline DISTANCE_EXP to match libjxl default
MERGED Fix rect bounds check for padded images
MERGED Remove zerocopy from production dependencies

HDR Support:

MERGED Implement HDR tone mapping for ICC profile generation

CI & Releases:

MERGED Bump version to 0.2.2
MERGED Bump version to 0.2.1
MERGED Add jxl-perfhistory benchmark CI stage

Open PRs:

IN REVIEW Add i16 sample type support for modular decoding
IN REVIEW Add jbrd box support for JPEG reconstruction
MERGED Add SIMD optimization for int_to_float conversion
ABANDONED Add WebAssembly decoder with browser demo
IN REVIEW Add ISO 21496-1 gain map support

JPEG XL Chromium Integration

MERGED Add jxl-rs to third_party
MERGED Add JXL infrastructure: enums and build flag
MERGED Roll jxl: 0.1.5 => 0.2.0
MERGED Roll jxl: 0.2.0 => 0.2.1
MERGED Roll jxl: 0.2.1 => 0.2.2
MERGED Add JXL image decoder using jxl-rs
MERGED Wire up JXL decoder

Chromium CLs In Progress

Active CLs currently under review:

Web Platform / Network:

IN REVIEW Add user-select: none to button, meter, progress, select
MERGED Add Request.isReloadNavigation attribute
MERGED Preserve MIME type in URL parser
MERGED Preserve %2E encoding in URL paths
MERGED Allow data: URL redirects in manual mode
ABANDONED Complete HTTPS-RR support
IN REVIEW Fix document.activeElement stuck after programmatic iframe focus

Accessibility:

MERGED Always return kForm for native form elements
MERGED Expose named forms as ATK_ROLE_LANDMARK
IN REVIEW Fix crash on profile-dependent flags

Linux/Ozone:

IN REVIEW Pass DRM modifiers for Y/UV planes in NativePixmapEGLBinding

Extensions:

IN REVIEW Add theme.getCurrent() WebExtensions API

Code Modernization

MERGED Environment::GetVar series (9 CLs) - Modernized to std::optional
MERGED Move PseudoTcp to remoting/protocol
MERGED Refactor StartupBrowserCreator for readability
MERGED Replace WTF::NotNullTag with base::NotNullTag

Other Open Source

MERGED Add tui.alternate_screen config and --no-alt-screen CLI flag for Zellij scrollback - OpenAI Codex
MERGED Add plan mode for safe code analysis - Pi Coding Agent
MERGED Add configurable keybindings system - Pi Coding Agent

Links

Resource	URL
All Chromium CLs	chromium-review.googlesource.com
All PDFium CLs	pdfium-review.googlesource.com
All jxl-rs PRs	github.com/libjxl/jxl-rs
GitHub	github.com/hjanuschka