ANGLE is under continuous development, and does not create release tarballs or tag specific revisions as releases, which may make the process of choosing a point in ANGLE's history as the dependency for your project less than obvious. This document illustrates how to choose a branch of ANGLE which can be expected to be updated with critical fixes, should they be needed.
Branches are created automatically in ANGLE to correspond to branches created in Chromium. These branches are named chromium/####, where the number is the matching Chromium branch. These branches will be created from the revision which that Chromium branch points to as its dependency. So, for example, the chromium/2013 branch point is at r28bcf4ff, because [Chromium's dependency file for the 2013 branch] (http://src.chromium.org/viewvc/chrome/branches/2013/src/DEPS?revision=272741) uses this ANGLE revision.
It isn't necessary to be familiar with how Chromium's dependency management works to choose an appropriate ANGLE branch for your project. You will, however, likely want to make sure that you choose a branch that is used for a relatively stable Chromium release channel build, as those branches will be deployed with Chromium, and receive updates if bugs are found and fixed during release lifetime, while the more volatile channels will turn over quickly, and their branches will be short-lived.
We recommend choosing a branch corresponding to a Beta or Stable Chromium release if you are pursuing periodic, not continuous, integration of ANGLE.
In order to determine which branches are used by Chromium releases, please use the OmahaProxy tool, which lists build information about current Chromium releases. Find the entry for a suitable release channel (for now, we recommend one of the Windows desktop releases), and note the branch listed in the true_branch column. This identifies the ANGLE branch used by that Chromium release.
If bugs (stability, security, performance, or otherwise) are discovered after a branch has been created, and that branch is used by a Chromium release, the fixes for those bugs will be applied to the ANGLE branches for uptake by Chromium and any other projects using that branch. You should need only to perform a git pull to check for and apply any such changes.
Occasionally a bug fix must be merged back to an earlier Chromium release branch. To do this, first look up the branch number in OmahaProxy. For example, M55 corresponds to branch number 2883.
In the simple case where there are no conflicts, the merge can be done entirely in the Gerrit UI. Click the "Cherry pick" button and enter chromium/[branch_number] as the branch to merge to.
If there are conflicts, however, follow these steps:
git checkout chromium/[branch_number]git cherry-pick [commit_hash]git cl uploadHave the cherry-pick reviewed, and then land it. It's also OK to skip the review and land it yourself with TBR= in the issue description, if you have that ability.
There is one final step to pick up the ANGLE change into a Chromium Beta or Stable branch. A Skia auto-roller updates the DEPS file in the corresponding Chromium branch automatically once the ANGLE change is merged into an ANGLE branch. To make sure that your change has made it into Chromium you can check these auto-rollers: