Contains a written down set of principles and other information on //base. Please add to it!
Chromium is a very mature project. Most things that are generally useful are already here and things not here aren't generally useful.
Base is pulled into many projects. For example, various ChromeOS daemons. So the bar for adding stuff is that it must have demonstrated wide applicability. Prefer to add things closer to where they're used (i.e. “not base”), and pull into base only when needed. In a project our size, sometimes even duplication is OK and inevitable.
Adding a new logging macro
DPVELOG_NE is not more clear than just writing the stuff you want to log in a regular logging statement, even if it makes your calling code longer. Just add it to your own code.
If the code in question does not need to be used inside base, but will have multiple consumers across the codebase, consider placing it in a new directory under components/ instead.
Owners are added when a contributor has shown the above qualifications and when they express interest. There isn't an upper bound on the number of OWNERS.