[IMPORTANT] Experimental features in Chromium derivatives

[Andrew R. Whalley]

(BCC teams/individuals with Chromium derivatives)

Greetings!

If you build Chromium for end users, please ensure you set build flags
correctly to prevent functionality or stability problems.

To improve testing coverage, Chromium developer builds enable all
experimental features by default, even some which are not ready to be
shipped to end users. Unfortunately, many Chromium derivatives ship with
the same settings, which can cause problems. In particular, such builds of
M56 enabled two features which when combined had a bug
<https://bugs.chromium.org/p/chromium/issues/detail?id=693943> that caused
SSL connection failures against some servers.

Chromium packages and derivatives must set the following build flag
<https://chromium.googlesource.com/chromium/src/+/master/tools/gn/docs/quick_start.md>
for an end-user configuration:

fieldtrial_testing_like_official_build=true


This flag sets all field trials to their default states. See also the original
announcement
<https://groups.google.com/a/chromium.org/d/msg/chromium-packagers/UmdUH3AkQRE/TifdFA-OAgAJ>
and some more context
<https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/cdzrXjgHflM>
.

In a later revision, we will be revising the build flags to better
distinguish end-user builds from developer builds. We will send another
announcement to the chromium-packagers
<https://groups.google.com/a/chromium.org/forum/#!forum/chromium-packagers>
group once the change is made.* If you maintain a Chromium package or
derivative, please join that group to be informed of this and future
announcements.*

Cheers,

Andrew on behalf of the Chrome team