The two are roughly the same, the former was added when we couldn't use aura. Now that mash uses aura we can remove WmActivationObserver. This means class that subclasses WmActivationObserver should be converted to subclass aura::client::ActivationChangeObserver and registration should move to Shell::GetInstance()->activation_client()->AddObserver().
Once this is done, WmShell::AddActivationObserver/RemoveActivationObserver can be removed.
Comment 1 by sky@chromium.org
, Mar 7 2017Status: Started (was: Available)