Chrome SDK

A native macOS SDK built on Chromium, with a Swift API for embedding the browser engine. Used by Cobble. Independent project; not an official Google SDK. This repository contains the Swift API, a narrow native bridge, patches against a pinned Chromium release, and an independent test harness. It does not contain a Chromium checkout. Matched development runtimes are published as immutable GitHub Release assets; they are not release-qualified app downloads.

ABI	18 (development; matched runtime required)
Engine	Chromium 153.0.8010.37, pinned in chromium.lock.json
Platform	Apple Silicon macOS
Source	Swift 6, Objective-C++, C++, Python
Status	Development build; no release signing or notarization

The app embeds Chromium's real framework, helpers, and resources. The Swift package alone does not render pages. Cobble also builds separately with WebKit.

See AUDIT.md for the feature inventory, known gaps, ownership map, and validation limits. Existing APIs do not imply full Chrome UI compatibility.

Development workflow

This public repository is the source of truth. Work on branches or temporary worktrees here; the former private SDK repository is archived. Cobble pins an exact SDK commit, and Full packaging requires that commit’s matched runtime, ABI, source lock and native-payload hashes. Keep one incremental Chromium work directory outside Git. Keep packaged runtimes outside the source checkout and retain one rollback runtime instead of copying source/build trees.

ABI 18 adds runtimeInfo(), structured main-frame navigation failures, load progress/document readiness, primary-renderer health, native history entry selection, case-sensitive/count-only find, initial find text, and download source, MIME, byte-count and interruption metadata. Download MIME is Chromium's effective type and may reflect the filename's native mapping rather than the response header alone. This client requires a rebuilt ABI 18 runtime; ABI 17 binaries cannot load it. Recoverable download failures preserve callbacks through repeated retries, and an empty private-window key is rejected.

ABI 17 adds ChromiumRuntime.onPopupWithDisposition, delivering the created child’s exact opening intent. Command-click and middle-click children can stay in the background; ordinary popups and Shift-modified children activate. The legacy onPopup callback remains available for hosts that always activate.

Lightweight source and Swift checks run in CI. Chromium-update discovery opens a review proposal; native builds remain manual, and checkpoint uploads default to off. A lock update alone never qualifies or publishes a runtime.

Build

The source checks need Python 3 and Node.js. The Swift package needs Xcode:

python3 -m unittest discover -s Tests -p 'test_*.py'
node Tests/test_smoke_fixture.mjs
swift test
swift build --product CobbleChromiumClient

A full engine build needs an Apple Silicon Mac, Xcode, Chromium's source dependencies, and at least 100 GiB of free space. The driver downloads the exact Chromium and depot_tools commits in chromium.lock.json, then applies this repository's chromium/overlay and chromium/patches. Use a dedicated work directory outside this repository:

WORK=/path/to/chromium-build
python3 scripts/build.py preflight --work "$WORK"
python3 scripts/build.py prepare --work "$WORK"
python3 scripts/build.py configure --work "$WORK" --variant sdk
python3 scripts/build.py probe --work "$WORK" --variant sdk
python3 scripts/build.py compile --work "$WORK" --variant sdk
python3 scripts/build.py package --work "$WORK" --variant sdk

The build produces an unbranded Chromium.app and an SDK archive named with the engine version, SDK revision and native-payload fingerprint. Packaging refuses existing output and checks the source lock, overlay, patch hashes, exports, and successful build receipt. Use package --artifacts /path/to/new-output to keep immutable archives outside the source checkout; the default is ignored artifacts/. To run the independent harness:

python3 scripts/assemble_harness.py "$WORK/src/out/Cobble/Chromium.app" \
  --output '/tmp/Cobble Chromium Harness.app'
node scripts/smoke.mjs '/tmp/Cobble Chromium Harness.app'

The build can take hours and substantial memory. --jobs controls native build parallelism (default: 3). Builds for a new Chromium release require patch review and fresh runtime validation; changing the lock alone is insufficient.

Layout

• Sources/CobbleChromium/: Swift process (ChromiumRuntime), profile (ChromiumContext), page (ChromiumPage), consent (ChromiumPrompts) and service APIs.
• Sources/CCobbleChromium/: dynamic loader for the native bridge.
• chromium/overlay/ and chromium/patches/: additions and changes to the pinned Chromium source.
• Sources/ChromiumHarness/ and scripts/smoke.mjs: isolated native behavior checks.
• scripts/build.py: source preparation, build, provenance checks, and packaging.

Limits

The unbranded runtime enables H.264/AAC for MP4, Media Source Extensions and HLS. This does not add Widevine or other DRM support.

The project is under development. The packaged runtime is marked release_ready: false. Distribution signing, notarization, broad website compatibility, accessibility, performance, DRM, and some authentication flows remain unqualified. Do not treat the harness or source checks as a release gate.

License and attribution

Original Cobble SDK code in this snapshot is licensed under GPLv3. The previous BSD grant remains available for earlier copies. Chromium code appearing in the patches retains Chromium's license; its other third-party components retain their own notices. The build packages Chromium's generated credits. chromium/THIRD_PARTY_NOTICES.md records the Mori Browser attribution for the native adapter structure.