Manually updating Chromium to a new Fuchsia SDK

Normally the Fuchsia SDK dependency is automatically updated to a recent build on a regular basis, by the Fuchsia SDK AutoRoll Bot.

Should you need to manually update the SDK dependency for some reason, then:

Check the Fuchsia-side job for a recent green archive. On the “SUCCEEDED” link, copy the SHA-1 from the gsutil.upload link of the upload fuchsia-sdk step.
Put that into Chromium's src.git build/fuchsia/linux.sdk.sha1.
gclient sync && ninja ... and make sure things go OK locally.
Upload the roll CL, making sure to include the fuchsia trybot. Tag the roll with Bug: 707030.

If you would like to build an SDK locally, tools/fuchsia/local-sdk.py tries to do this (so you can iterate on ToT Fuchsia against your Chromium build), however it's simply a copy of the steps run on the bot above, and so may be out of date.

In order to sync a Fuchsia tree to the state matching an SDK hash, you can use:

jiri update https://storage.googleapis.com/fuchsia-snapshots/<SDK_HASH_HERE>

If you are waiting for a Zircon CL to roll into the SDK, you can check the status of the Zircon roller. Checking the bot's list of CLs might be useful too.

Another useful command, if the SDK was pulled by cipd (which it is in Chromium-related projects like Crashpad, instead of directly pulling the .tar.gz), is:

cipd describe fuchsia/sdk/linux-amd64 -version <CIPD_HASH_HERE>

This description will show the jiri_snapshot “tag” for the CIPD package which corresponds to the SDK revision that's specified in linux.sdk.sha1 here.